THORLABS EDU-OT3 User manual
EDU-OT3
EDU-OT3/M
Portable Optical Tweezers
User Guide
Portable Optical Tweezers Kit
Table of Contents
Chapter 1 Safety ............................................................................................ 1
1.1. Warning Symbol Definitions..................................................... 1
1.2. Laser Radiation Warning ......................................................... 1
Chapter 2 Product Description .................................................................... 2
Chapter 3 Principles of Optical Tweezers ................................................... 4
3.1. Dipole Approach in the Rayleigh Scattering Regime R <<
λ
....... 4
3.2. Geometrical Optics Approach in the Mie Regime R >>
λ
........... 6
Chapter 4 Kit Components ......................................................................... 16
4.1. Trapping Laser Source.............................................................16
4.2. Beam Expander.......................................................................17
4.3. Right-Angle Mirrors ................................................................18
4.4. Sample Positioning System .....................................................19
4.5. Microscope .............................................................................20
4.6. Additional Components...........................................................22
4.7. Included Hardware .................................................................23
4.7.1. Imperial Kit .............................................................................................. 23
4.7.2. Metric Kit ................................................................................................. 24
Chapter 5 Setup and Adjustment ............................................................... 25
5.1. Assembly ................................................................................25
5.1.1. Trapping Laser Source ............................................................................ 26
5.1.2. Beam Expander ...................................................................................... 28
5.1.3. Microscope .............................................................................................. 33
5.1.4. Sample Positioning System .................................................................... 40
5.2. Controller and Software Setup ................................................44
5.2.1. LED Controller ......................................................................................... 44
5.2.2. Laser Controller ....................................................................................... 44
5.2.3. Camera ................................................................................................... 46
5.2.4. Sample Positioning Stages ..................................................................... 50
5.2.5. Kinesis Settings ....................................................................................... 53
5.3. Camera Adjustment ................................................................54
Portable Optical Tweezers Kit
5.4. Beam Adjustment .................................................................. 55
5.5. Trapping, Microscope Focus, and Final Alignment.................. 58
Chapter 6 Experiments ............................................................................... 63
6.1. Creating a Sample.................................................................. 63
6.2. Setting the Correct Focus Level............................................... 64
6.3. Arranging the Silica Beads ..................................................... 65
6.4. Manipulating a Dairy Cream Particle in a Cream/Water
Emulsion ................................................................................ 66
6.5. The Holding Force of the Optical Trap .................................... 68
6.5.1. Brownian Motion ...................................................................................... 68
6.5.2. The Maximum Holding Force .................................................................. 71
6.6. Other Samples ....................................................................... 72
Chapter 7 Teaching Tips ............................................................................ 74
Chapter 8 Control via Game Controller .................................................... 83
Chapter 9 Troubleshooting ........................................................................ 86
Chapter 10 Regulatory .................................................................................. 88
Chapter 11 Thorlabs Worldwide Contacts .................................................. 89
Portable Optical Tweezers Kit Chapter 1: Safety
Rev B, February 15, 2022 Page 1
Chapter 1 Safety
1.1. Warning Symbol Definitions
Below is a list of warning symbols you may encounter in this manual or on your device.
Warning: Laser Radiation
1.2. Laser Radiation Warning
The class 3B laser diode used in this kit can emit more than 50 mW of optical power,
which can cause damage to the eyes if viewed directly. The laser driver is equipped with
a key switch and safety interlock, which should be used appropriately to avoid injury.
Additionally, we recommend wearing appropriate laser safety glasses
when using this kit.
WARNING
Portable Optical Tweezers Kit Chapter 2: Product Description
Page 2 MTN024417-D02
Chapter 2 Product Description
For many people, moving and controlling objects with a beam of light sounds more like the
“tractor beams” of science fiction than reality. However, optical tweezers are devices that
allow precisely that kind of manipulation. Many areas of research use them to measure
small forces on the order of piconewtons1. More exotic applications include the control of
tiny microgears2. Biologists use optical tweezers to manipulate different types of molecules
and cells3. In-vitro fertilization of ova is a typical application example – sperm can be
inserted into ova without mechanical contact, thus maintaining a sterile environment.
In a lab course, various demonstrations and experiments can be performed with an optical
tweezers setup. This kit can be used to carry out basic experiments such as moving small
spheres or cells through a solution. The kit can also be used for more advanced
experiments such as investigating the Brownian motion of objects, and measuring the
optical forces of the tweezers.
The working principle can be explained using concepts usually known to undergraduate
students, such as geometric optics, basic theory of Brownian motion, and Stokes’ friction.
It is an intriguing experience to be able to control objects with a laser beam – and not only
for students!
This Optical Tweezers Kit can be assembled into a complete and fully operating
experimental setup with which particles on the order of microns can be trapped and moved.
The beam path is schematically depicted in Figure 1. It is possible to perform a variety of
experiments using a number of different particles such as polystyrene beads, glass beads,
or starch grains from ordinary corn flour. A special feature of this setup is that it is portable.
It can be moved from room to room without needing disassembly or major readjustment,
making it ideally suited to demonstrate the principle of optical tweezers to students in
seminars or lecture halls.
Optical tweezers are not only intriguing scientific devices. Their inventor, Arthur Ashkin,
also received the 2018 Nobel Prize "for the optical tweezers and their application to
biological systems." As he wrote: “It is surprising that this simple [...] experiment, intended
only to show simple forward motion due to laser radiation pressure, ended up
demonstrating not only this force but the existence of the transverse force component [...]
and stable three-dimensional particle trapping."4
We recommend using the OTKBTK sample kit with the setup. The performance was
optimized for the sample slides and the cover glasses provided with the OTKBTK. For
simplicity, we designed the tweezers system to work without immersion oil.
1 K. SVOBODA, S.M. BLOCK: Optical trapping of metallic Rayleigh particles, Optics Letters 19
(1994) 13, 930-932
2 S.L. NEALE, M.P. MACDONALD, K. DHOLAKIA, T.F. KRAUSS: All-optical control of microfluidic
components using form birefringence, Nature materials 4 (2005), 530-533
3 J.E. MOLLOY, M.J. PADGETT: Lights, action: optical tweezers, Cont. Phys. 43 (2002) 43, 241-
258
4 Proc. Natl. Acad. Sci. USA, Vol. 94, pp. 4853-4860 (1997)
Portable Optical Tweezers Kit Chapter 2: Product Description
Rev B, February 15, 2022 Page 3
The light path through the optical tweezers experiment.
LED
Sample
Position
Laser
Camera
Microscope Beam Path
Laser Beam Path
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Page 4 MTN024417-D02
Chapter 3 Principles of Optical Tweezers
To describe the function of optical tweezers, we will examine the force that a focused laser
beam with a Gaussian intensity profile (the TEM00 mode) exerts on an object, which is near
or in the focus. Usually one also assumes that the object is a bead, which consists of a
dielectric, linear, isotropic, and spatially and chronologically non-dispersive material. In the
experiments described below, micron-sized beads made of polystyrene are primarily used.
It is customary to describe the force of the laser on the object by separating it into two
components. One component, the scattering force, acts along the direction of beam
propagation. The second component acts along the intensity gradient and is therefore
called the gradient force. The gradient force can act in different directions with respect to
the beam. As the laser has a Gaussian intensity profile, the gradient force can act
orthogonally to the beam, but it can also act parallel to the beam, as the laser is focused
and therefore also has an intensity gradient along the beam axis. These two components
and their relationship to one another are the defining factors for whether or not a particle
can be trapped by the optical trap. Stable optical tweezers are only obtained if the gradient
force, which pulls the object in the direction of the focus, is greater than the scattering
force, which pushes the particle in the direction of the beam away from the focus.
The various theoretical approaches to describe optical trapping can roughly be divided
according to the areas in which they are valid. The relationship of the radius (or diameter
) of the bead to the wavelength of the incident laser beam is the dividing factor. The
case is theoretically very complex and shall therefore not be dealt with here. The
two extreme cases for very large and very small particles are summarized below:
3.1. Dipole Approach in the Rayleigh Scattering Regime R << λ
The first case we will consider is when the radius of the bead is significantly smaller than
the wavelength of the incident laser beam. Then, the electrical field
() is approximately
spatially constant with respect to the particle and the situation can be portrayed as follows:
As the bead is assumed to be dielectric, one can imagine it as a collection of point
dipoles. Due to their polarizability, a dipole moment
is induced in each of the point
dipoles by the incident laser beam. Due to the linearity of the material, the following applies:
=
(
)
(1)
Here, is the location of the i-th point dipoles and
() is the electrical field strength at
this location. In addition, the electrical field of the laser appears to be approximately
spatially constant for the bead due to the condition , meaning that at a certain point
in time 0 the strength of the electrical field is equally great for all point dipoles of the bead.
As a result, the induced dipole moment is equally great for all point dipoles. The
polarization
resulting from the induced dipole moments is then
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Rev B, February 15, 2022 Page 5
=
1
=
=0
(2)
where is the electrical susceptibility, 0 is the electrical constant, and is the volume of
the bead. The potential energy of one of the point dipoles with dipole moment in the
electrical field
is =
. Because there are point dipoles in a bead with the volume
, the energy density in the bead is defined by:
=
=
=
(3)
The occurrence of the gradient force, which is a force component that is directed in the
direction of the intensity gradient of the incident electrical field, can be explained when one
observes this potential energy of the bead in the electrical field. Equation (2) states that
is proportional to
. Therefore, according to equation (3), is proportional to
and
thus to intensity
of the incident field. The force exerted on the particle by the
incident field is proportional to the gradient of the potential energy and therefore
proportional to the intensity gradient . The following equations describe the gradient
force:
=
2
2 (4)
=
1
+ 2(5)
=
(6)
Here, is the polarizability of the dipoles and is the relationship of the refraction index
of the particles, (polystyrene in our case) to the refraction index of the surrounding
medium, (water in our case).
The destabilizing scattering force component is explained by the scattering of the incident
light at the particle. The force action is created by the absorption and isotropic re-emission
of the light by the bead. As , the conditions are fulfilled for Rayleigh scattering. The
resulting force can be stated as follows:
=
(7)
= 128
3 1
+ 2
(8)
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Page 6 MTN024417-D02
Here, is the speed of light in vacuum and is the incident intensity and is the scattering
cross-section of the incident light. It is important to note that the scattering force is
proportional to the intensity and points in the beam direction.
3.2. Geometrical Optics Approach in the Mie Regime R >> λ
This ray optical approach deals with the second possible extreme case. Here, we will
assume that the radius of the bead is much larger than the wavelength of the incident
laser. In this range, the conditions of geometric (ray) optics are fulfilled and one can think
of the laser beam as a bundle of rays. Typically, this assumption is valid for beads with a
radius that is greater than 10. The basics of the theoretical derivation of the gradient
and scattering force in accordance with this model can be found in a work by Ashkin5.
The particle properties of light must now be taken into account, namely that light can
transfer momentum to an object in the form of photons. The force action of a beam on a
particle can be explained using Newton’s second law: the force on a particle is exactly
equal to the change in the momentum of the particle over time:
=
(9)
The following equation describes the change in momentum
of a beam over time in a
medium with a refractive index :
=
=
() (10)
Here, () is the intensity distribution in the beam cross-section. Often, a Gaussian profile
is used, in which the intensity decreases in a Gaussian distribution from the center of the
beam outward. This is also the case in our setup.
If a beam with the power hits a sphere at an angle of , part of the beam will be
reflected and part of it will reach the interior of the sphere through transmission (see Figure
2). For the power of these two partial beams, the following is in effect:
= (11)
= (12)
Here, is the reflectivity and is the transmissivity. The transmitted beam transports
momentum into the sphere in accordance with the equation (10).
5 Ashkin A., Forces of a single-beam gradient laser trap on a dielectric sphere in the ray optics regime.
In: Biophys. J. 61 (1992) 2, 569-582
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Rev B, February 15, 2022 Page 7
Reflection and Transmission of an Incident Partial Beam on the Inside and
Outside Surfaces of a Sample Bead with a Refractive Index Higher than the
Immersion Medium
Inside the sphere, the beam is reflected and transmitted numerous times. Part of the beam
is repeatedly reflected on the sphere's internal wall and remains in the sphere, while the
rest exits the sphere again through transmission. The beams which exit the sphere again
were thus subject to a change in momentum
. The force on the sphere is equal to the
momentum per unit time that remains in the sphere, based on equation (9). Now, the force
on the sphere is once again divided into two components: a component in the direction of
the incident beam (corresponds to the Z direction) and a perpendicular component
(corresponds to the Y axis). This results in the following for both forces:
=
(13)
with the Q factor
= 1 + cos(2)
2(
cos
(
22
)
+cos
(
2
))
1 +
2+ 2cos(2)(14)
and
≡
=
(15)
with the Q factor
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Page 8 MTN024417-D02
=sin(2)
2(
sin
(
22
)
+sin
(
2
))
1 +
2+ 2cos(2)(16)
Here, is the angle at which the first transmitted beam is refracted toward the normal (see
Figure 2). According to Snell’s law of refraction, the following relationship is in effect for
the angles and :
sin
(
)
sin()=
(17)
and are dimensionless Q factors, which state what percentage of the incident
momentum contributes to the force parallel or perpendicular to the beam, respectively.
These factors depend heavily on the angle of incidence of the beam, as one can see from
the equations. This angle becomes larger the more heavily the beam is focused, which
occurs when a higher numerical aperture objective is used.
The component of the beam that points in the incident direction (Z direction) ultimately
causes the scattering force . The component perpendicular to this (Y direction) is mainly
responsible for the gradient force . In order to obtain the overall power, one must
naturally consider all partial beams and integrate all of them. That will be discussed in
detail below.
Q Factor Angular Dependence5
Figure 3 shows the values of the two factors, depending upon the angle of incidence
when the focus is located slightly above the surface of the sphere. One can see here
is negative through almost the entire range, meaning the force acts in the negative Y
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Rev B, February 15, 2022 Page 9
direction, which is upwards in Figure 2. The factor is always positive. The Z-component
of the force therefore always points in the beam direction. If the beam were not to hit in the
upper half of the sphere, but rather in the lower half, one can easily conclude for reasons
of symmetry that the direction of the component would reverse, the direction of the Z-
component would remain the same.
In short: The sphere always moves into the focus or the point of highest intensity. In order
to ultimately achieve a stable optical trap, the following must be true:
>
(18)
In the following, we’ll discuss these forces in more detail.
Total force on the sphere
To obtain the total force acting on the sphere, we have to sum over all partial beams that
hit it.
For that, we integrate (i) over the distance between the partial beam and the symmetry
axis of the whole beam, ranging from 0 to , and (ii) over its angular coordinate ,
ranging from 0 to 2.
Figure 4 shows how the coordinates and of a partial beam (in red) are defined. The
dashed line stands symbolically for the sphere the laser is focused on.
Coordinates of a Partial Beam
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Page 10 MTN024417-D02
So far, the force was given as a function of which now has to be expressed in terms of
and . Figure 5 shows a partial beam incident on the sphere with angle from the side.
The following statements hold true:
=sin =sin
(19)
and
sin =
+
(20)
roughly corresponds to the focal length of the objective. Effectively, you can use the
objective’s working distance for this parameter.
Relation Between and
.
6
Then, can be expressed as
()=arcsin
+ (21)
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Rev B, February 15, 2022 Page 11
Next, the forces need to be summed. For that, we start by observing Figure 6. A partial
beam with distance to the symmetry axis of the whole beam falls on the sphere under
an angle . As discussed above, we can split the resulting force in two perpendicular
components, and . For clarity, we can now add another partial beam, namely the one
mirrored on the symmetry axis, denoted “mirror beam”. As sketched in Figure 6, this partial
beam falls on the sphere on the other side and results in “mirrored” force vectors ,
and , in the right part of the sphere (which were not drawn to avoid an overcrowded
figure).
The Contribution of One Ray to the Total Force5,6
When you consider all of the partial beams with the same condition around the symmetry
axis, it immediately becomes clear that all force components in X and Y direction vanish
and only resulting force components along the Z axis remain.
These can be written as
,=sin=
+(22)
,=cos =
+(23)
where , is pointing in the negative Z direction and is, therefore, negative. Hence, each
infinitesimal force contributing to the total force is given by
=
cos
sin
(24)
6 Adapted from A. Langendörfer: ”Aufbau einer Optischen Pinzette für das Landesmuseum für
Technik und Arbeit in Mannheim“, wissenshaftliche Arbeit, KIT, Karlsruhe, 2009
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Page 12 MTN024417-D02
The total force is the sum of the total scattering force , and the total gradient force
, , where
, = cos
(25)
and
, = sin
(26)
In Figure 7, we plotted the gradient force, the scattering force and the resulting total force
as a function of the focus position relative to the radius of the sphere. The direction is
the Z axis, meaning that the plot shows the behavior when the focus is moved through the
center of the sphere from bottom to top. The curves were calculated with the above
equations with a set of typical parameters since we only want to discuss the curve’s
general form. Therefore, the forces are given in arbitrary units (a.u.). On the horizontal
axis, “+1” corresponds to the focus position on the sphere’s outer surface right above the
sphere’s center while “-1” corresponds to the lower surface below the center.
Overview of All Forces When Focus is Changed in Z-Direction6
From Figure 7, we learn that
1. The gradient force always points towards the focus. For example, when /0,
the focus is above the sphere’s center. Then 0 and the gradient force pushes
the sphere upwards into the focus.
2. The scattering force always points in the direction of propagation of the incident
beam, in this case downwards. Note that 0 in the entire range of the plot.
Force [a.u.]
Gradient force,
,
Scattering force, ,
Total force,
Location of the focus in units of the sphere radius (Z direction)
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Rev B, February 15, 2022 Page 13
3. When the focus is below the sphere’s center, i.e. /0, scattering and gradient
force act in the same direction. When the focus is above the sphere’s center,
i.e. /0, both forces point in opposite directions.
We also note that the absolute value of the gradient force is always higher than the
absolute value of the scattering force. This is the requirement for any stable optical
tweezers trap. The fundamental quantity to fulfill this requirement is the microscope
objective’s numerical aperture, which defines the angle of the focus which we will discuss
next.
Sometimes the focus is not above or below the sphere’s center but along the y-axis
instead. Again, the reference axis goes through the sphere’s center, and we plot the
occurring forces as a function of the focus’ distance to the sphere’s center in units of the
sphere’s radius.
Figure 8 shows the gradient force and the scattering force. Plotting the sum of both forces
would not make sense as they point in different directions (, in Z direction and , in
Y direction).
From Figure 8, we learn that:
1. The general form of the curves is similar to the focus’ movement on the Z axis.
Only outside of the sphere the force decreases a little faster than compared to
the Z axis.
2. The maximal gradient force is larger than the maximal scattering force (absolute
values). This is the case when the parameters such as the numerical aperture
allow optical trapping.
3. The maximal gradient force are located just within the sphere, close to the
surface. The maximal value of the scattering force is found right on the surface.
Scattering and Gradient Force with the Focus Changed in Y Direction6
Gradient force,
,
Scattering force, ,
Force [a.u.]
Location of the focus in units of the sphere radius (Y direction)
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Page 14 MTN024417-D02
Influence of the Numerical Aperture
As we have seen above, the angle of incidence of the partial rays plays a crucial role in
optical tweezing. The angle is defined by the numerical aperture of the objective: the
numerical aperture ( ) describes the acceptance cone of an objective and is given by
= sin (27)
where is the refractive index of the material between the objective and the focus and
is half of the angle of the maximum light cone.
As discussed, the gradient force ,needs to exceed the scattering force
, to get a stable trap. Next, we want to investigate a measure for the trap’s
strength. For that, we can have a look at the ratio of , and , at the
point / = 1 since we have shown that scattering and gradient force are strongest
when the laser focus is at/near the sphere’s surface (i.e., || = 1). So for a stable
trap, we can assume the condition7:
,(
= 1)
,(
= 1)
1 (28)
Absolute values are used since , is negative. Figure 9 shows how this strength
depends on the numerical aperture. Again, we plotted a curve with typical parameters to
show the general behavior of the curve; therefore, we do not focus on the concrete
numbers.
Figure 9 shows the fundamental behavior that the strength of the trap increases with
increasing numerical aperture. Also, it becomes apparent that there is a lower limit for the
numerical aperture of the objective. Below that, no trapping occurs since the gradient force
never exceeds the scattering force.
Behavior of the Trap’s Strength with Respect to the Numerical Aperture6
7 The absolute value of the forces is used since , is negative.
|,/ ,|
Numerical aperture
NA=n. sin(phi)
Fg,tot
Fg,tot
Fg,tot
Fs,tot
Fs,tot
Fg,tot(S/R=1)
Fs,tot(S/R=1)
1
| Fg,tot / Fs,tot |
Portable Optical Tweezers Kit Chapter 3: Principles of Optical Tweezers
Rev B, February 15, 2022 Page 15
Influence of the Laser Power
While the numerical aperture affects the ratio of gradient and scattering force, the laser
power directly influences the individual forces. In Equations (13)
=
and (15),
≡
=
we see that both forces increase proportionally with the laser power . When the laser
power is increased, each individual force gets stronger. However, their ratio (which
essentially determines if optical tweezing ocurrs or not) remains the same, see Equation
(28).
Combining what we know about the numerical aperture and laser power, we can note that
the increase in trapping strength can be achieved through two factors:
•Increase of the numerical aperture of the objective so that the gradient force
exceeds the scattering force.
•Increase of the laser power, which increases the tweezer’s strength linearly if the
condition , > , is met.
This also tells us that increasing the numerical aperture is the more effective way to
improve trapping than increasing the laser power. While the laser power increases the
trapping force linearly, Figure 9 shows a stronger than linear behavior above the trapping
limit.
Portable Optical Tweezers Kit Chapter 4: Kit Components
Page 16 MTN024417-D02
Chapter 4 Kit Components
In cases where the metric and imperial kits contain parts with different item numbers,
metric part numbers and measurements are indicated by parentheses unless otherwise
noted.
4.1. Trapping Laser Source
1 x SR9A-DB9
ESD Protection and Strain
Relief Cable
1 x L658P040-S
658 nm, 40 mW,
Ø5.6 mm, A Pin Code
Laser Diode8
1 x LTN330-A
Adjustable Collimator for
Ø5.6 mm Laser Diodes,
AR Coated: 350 – 700 nm
1 x KLD101
K-Cube Laser Diode
Driver
1 x TPS002
±15 V / 5 V K-Cube
Power Supply 1 x RS3.5P8E
(RS3.5P4M)
Ø1" (Ø25 mm) Pedestal
Post, 3.5" (90 mm) Tall
1 x CF125
Small Clamping Fork 1 x KC1-T(/M)
Ø1" Cage-Compatible
SM1-Threaded Mirror
Mount
1 x AD15F
SM1-Threaded Adapter for
Ø15 mm Components
8 The L658P040-S is a wavelength-screend L658P040. This ensures that the
center wavelength is in the range between 656 nm and 660 nm.
Portable Optical Tweezers Kit Chapter 4: Kit Components
Rev B, February 15, 2022 Page 17
4.2. Beam Expander
2 x ER10
Ø6 mm Cage Assembly
Rod, 10" Long
2 x ER1
Ø6 mm Cage Assembly
Rod, 1" Long
2 x ER3
Ø6 mm Cage Assembly
Rod, 3" Long
2 x ER6
Ø6 mm Cage Assembly
Rod, 6" Long 2 x CP45(/M)
30 mm Removable
Segment Cage Plate
2 x CP45T(/M)
30 mm Removable
Segment Cage Plate,
Thick
1 x LA1509-A
Ø1" N-BK7 Plano-Convex
Lens, f = 100 mm
AR Coating: 350-700 nm
1 x SM1A6
Adapter with External
SM1 Threads and Internal
SM05 Threads
1 x SM05L03
Ø1/2" Lens Tube,
0.3" Long
1 x LA1074-A
Ø1/2" N-BK7 Plano-
Convex Lens, f = 20 mm,
AR Coating: 350-700 nm 1 x TR3 (TR75/M)
Ø1/2" (Ø12.7 mm) Post,
3" (75 mm) Long
1 x PH3 (PH75/M)
Ø1/2" (Ø12.7 mm) Post
Holder, 3" (75 mm) Long
This manual suits for next models
1
Table of contents
