Restraining Collar
this was a speciallized device that was used to limit the functions of a droid. Unlike a restraining bolt, which was welded to a droid's plating and could cause damage when removed, a restraining collar was a large device that was slipped around the droid's body to keep it from moving around. These devices worked well for astromech and other droids that moved about on wheels, and lacked arms or other mechanisms for detaching the collar.