This is a reversible, interior side lock for garage doors from Ideal Security. The sliding bolt, locking lever, and release mechanism are all spring-loaded. These allow it to be operated from the outside, with the addition of an exterior handle for locking and/or a lock cylinder for unlocking. It also works with centered exterior handles which use cables to operate one or two interior side locks at either end of the door. Related accessories (sold seperately) include the SKT9303 and SKL9201 exterior handles, used to lock from the outside; a lock cylinder, used to unlock from the outside; the SK7135 latch cables, used to lock from the outside with a centered exterior handle.