This term refers to locks that are designed to facilitate frequent rekeying without disassembling the lock. A special key called a control key is used to remove and replace the cylinder or core. Common uses for this type of lock are college campuses and retail stores where frequent rekeying is necessary.Impression
This refers to a method of fitting a key without disassembling it. It involves repeatedly inserting a key blank into the lock and gradually filing the key to fit. This is not a do-it-yourself project! Locksmiths spend years cultivating a knack for impressioning locks. Some locks are not suitable for this procedure no matter what the skill level of the locksmith.