Lock Synergy Economy Drop BoltThe Lock Synergy Economy Drop Bolt, model LSDB 600, is an electric drop bolt that is mounted on any door frame with a width of 1. 75 (44. 5mm) or more. When fully mortised, its compact design allows the lock to fit on frames with a depth of 1. 75 (44. 5mm). The 5 8 (16mm) stainless steel bolt has a 5 8 (16mm) throw, making forced entries difficult. The lock uses a magnetic sensor to sense the door position, thus locking the door when the door is in