This refers to locks that are installed on the surface of a door rather than inside the door (see cylindrical locks and mortise locks). They are fairly easy to spot, because the lock consists of a box bolted onto the inside of the door.Rekey
This refers to one of the most common services provided by locksmiths. It generally entails disassembling a lock to replace the “tumblers” inside. Once completed, the lock requires a different key to operate than before. This is done to house locks when people move, divorce, are robbed, etc. Businesses rekey frequently when any key-holding employee quits or is fired. Body shops and auto dealers have new replacement locks rekeyed to match their customer’s key before installing them in the vehicle. If a lock must be replaced on a home or business, often it can be keyed to match the other locks on the building.Restricted key system
This refers to various products available from professional locksmiths. If you buy such locks, you can be sure that no unauthorized duplicate keys will be made. Many businesses and institutions utilize such systems. If an employee’s key from a restricted set is returned upon their resignation, no rekeying is necessary (this can save thousands of dollars!). Other popular applications are neighborhood swimming pools, tennis courts, clubhouses and fitness centers. This allows the management to issue keys to those who pay their dues, certain that members cannot in turn make keys to share with other, non-paying acquaintances! NOTE: Stamping “do not duplicate” on an ordinary key is not very effective! Some locksmiths will require ID or a note on letterhead to duplicate such a key. But anyone can produce letterhead, and there is no way to verify authorization to duplicate. There is simply no way to control duplication of a key that is available at every locksmith shop, home improvement store, and shoe repair shop in the world. If you need to put an end to unauthorized duplication of keys at your home or workplace, you need to contact a professional locksmith for restricted key products!