A tapered lock is a form of keyless shaft locking device that does not require any material to be removed from the shaft. The basic idea is similar to a clamp coupling but the moment of rotation is closer to the center of the shaft. An alternative coupling device to the traditional parallel key, the tapered lock removes the possibility of play due to worn keyways. It is more robust than using a key because maintenance only requires one tool and the self-centering balanced rotation means it lasts longer than a keyed joint would, but the downside is that it costs more.