What do you call the rolling part of a combo lock? The rolling part that allows you to enter combinations to unlock the lock? What is it called?
Wikipedia seems to call them dials and/or discs:
A combination lock is a type of locking device in which a sequence of symbols, usually numbers, is used to open the lock. The sequence may be entered using a single rotating dial which interacts with several discs or cams, by using a set of several rotating discs with inscribed symbols which directly interact with the locking mechanism, or through an electronic or mechanical keypad.