A security rim lock offers enhanced protection and is primarily used for apartment doors in residential complexes. The rim lock is fitted to the door leaf as a supplement to the regular lock. While it is locked from the outside with a key, it is operated on the inside of the door using a bolt or rotary knob. A built-in locking bar ensures that the door can only be opened slightly, thus avoiding forced entry. Furthermore, a security rim lock makes attempted break-ins considerably more difficult.