the correct key is inserted, it will clear the wards and rotate about the center post. The key may then strike a lever, activating a latch or sliding bolt, or it may itself push against the latch or bolt. In a double acting lever lock, the key may additionally push against a spring-loaded lever which holds the sliding bolt in place. Vulnerabilities Due to the design of the lock, a well designed skeleton key can be made to bypass the wards. For this reason, warded lock mechanisms are generally used in low-security applications. There are also a very limited number of unique keys that can be created, so many keys will be able to open other doors that they were not designed to open. The invention of the lever tumbler lock solves this problem, as each lever is required to be lifted to a certain height in order to operate the locking mechanism. See also Skeleton keys Lever tumbler lock Padlocks Mortise lock References Locks (security device)