The REV Robotics Slim Shaft Collar is used to prevent gears, sprockets, wheels, and other parts from sliding out of place on a 5mm hex shaft when space is at a premium. Shaft collars can also be used to prevent the shaft itself from sliding out of its mounts. Once in place, the set screw is tightened on one of the flat sides of the hex shaft. As with the standard REV Shaft Collar, the set screw is M3 threaded, making it easy to replace the set screw with an M3 Hex Head bolt if teams prefer.  1.5mm Allen Wrench for use with set screws sold separately.