Lever tumbler lock

A lever tumbler lock is a type of lock that uses a set of levers to prevent the bolt from moving in the lock. In the simplest of these, lifting the tumbler above a certain height will allow the bolt to slide past.

The number of levers may vary, but is usually an odd number for a lock that can be opened from each side of the door in order to provide symmetry. A minimum number of levers may be specified to provide an anticipated level of security (see 5 Lever locks section).