This thumbscrew is used on Take-A-Label dispensers and applicators. It fits the metal collar. This screw is part of the assembly used to mount the labels onto the machine.
Commonly Lost Parts
If you are replacing this component on a Take-A-Label TAL-250 or TAL-450 dispenser (trip wire & photo eye), you may also want to review these other commonly lost parts:
Each machine also requires the correct waste wind clip:
Verify whether you have a TAL-250 or TAL-450 dispenser before ordering a waste wind clip, since each clip is specific to the machine width.