Tumbler keys are a type of key used in various locking mechanisms, particularly in pin tumbler locks. These keys have notches or grooves that align with internal pins in the lock, allowing the lock to turn and open when the correct key is inserted. The design of tumbler keys makes them relatively secure and difficult to duplicate without the original. The mechanism relies on a series of pins of different lengths, which are pushed up by the key. When the correct tumbler key is inserted, the pins align at the shear line, enabling the lock to turn. This system is commonly found in residential and commercial locks.