Locksmiths receive requests on a daily basis for securing “special” items in special ways. Often a locksmith can secure a special situation with normal hardware. However, there are many special locking devices for special situations.
Sliding doors are vulnerable to a variety of attacks. There are many different kinds of sliding doors, so locksmiths stock many different kinds of hardware for protecting them. It is the experience of the locksmith that allows selecting the proper hardware for a given door. The lock that will adequately protect one door against intrusion may not work well for another door.
Mailbox locks must meet standards set by the US Postal Service. Despite that, there are many different styles and brands of mailbox locks. Locksmiths will usually have dozens of different kinds of mailbox locks on hand, and the knowledge of which one fits what application.
Locks for office furniture, desks, file cabinets, tool boxes, and vending machines are a separate category. Like door locks, they come in different functions, sizes, and security levels. One lock, straight out of its package, can be installed dozens of different ways depending on the needs of the situation.