It is the bottom part of a laser holder. It attaches to Nerf Rival picatinny rails and makes it easier to hip-fire the blaster by showing the user where the dart will land. This part adjusts the x-axis (Left to Right) of the direction that the laser is pointing. The attachment point on top is 4.8 mm in diameter and half is cut off. All parts should slide together and the lid may need to be held down with small amounts of a thin tape if necessary.
Supports should be used but not on the worm gear, worm gear should be printed with the gear on top and thumb-screw part down
Worm Gear: https://www.mcmaster.com/57545K624/
Thumb Screw: https://www.mcmaster.com/90200A110/
AutoDesk Inventor
TinkerCad:
https://www.tinkercad.com/things/cifNgqEobCe-gear-v3
The author marked this model as their own original creation.