Locksmithing is the art of opening and closing locks without the use of the original key. A locksmith installs, repairs, changes and opens locks and combination locking mechanisms. They also make and duplicate keys.
Locksmiths are best known for their skills in emergencies when customers are locked out of their cars, homes or offices. In such cases locksmiths are required to pick the locks. They may also be required to duplicate keys by means of the impression or key code. Combination locks are opened by touch or by the use of a drill. They repair damaged locks by replacing tumblers, springs and other parts.
The locksmith also recommends security measures such as periodical re-keying (changing the locking mechanism to fit new key codes) for businesses. Some locksmiths, known as protective signal repairers, install and repair burglar and fire alarm systems.
Most locksmiths work irregular hours because they are on 24-hour emergency call. They therefore need to have the necessary equipment with them at all times.