Swift M3-M Use And Care Manual page 14

Two sets of well-cups with lids: These can be used to house even larger
objects such as rocks or live specimens.
Using the Comparison Bridge:
SETUP
The Bridge attaches to the top of the two M3 scope bodies. Please ensure
that you align the stickers on the front of the scope with the stickers on
the front of the bridge so that you have the left and right body in the
proper place.
Using the included allen key wrench, tighten the bridge onto the two
microscope bodies at the locking set screws located on the top right side
of each M3. Please do not, under any circumstance, pickup the unit by
the forensic bridge. If you need to move the unit from place to place,
use the blue hand grips on the back of each M3 body.
Next, mount the trinocular head onto the top middle of the comparison
bridge and tighten the corresponding locking set screw located on the
center front of the bridge with the included allen key wrench.
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