At Home Hardware Plus we offer four styles of locks for your mortise lock to fit whatever need you may have, offering you flexibility and traffic control in your commercial or industrial space. A mortise lock is the metal casing that holds the operating part of a lockset into a pre-cut mortise cut in the door. Mortise locks are considered a very strong and secure lock, since there is a hidden lock and its keyhole is only visible from the outside. Although complex in their aesthetic, mortise locks are supreme locks to provide you and your space protection.