Security Entrance Mortise Lock Features: 1 Latch response distance 2mm.Your door can be larger gap 2 Lesser parts inside than before,more reliable and better performance 3 Not brass parts,fire proof,above 1000. 4 Redesign most of parts in side.Better movement and tight tolerance. 5 Never stop or failure when the cylinder turn to special angle. 6 Redesign spindle,assemble tight with the square hole. Better turning performance 7 Redesign chamfer latch change side function.More easy to change the latch. 8 Not part will jump out when you open the cover.Easier to ssemble for manufacturer and few deviation. 9 50thousand cycled in-house testing,good spring inside. 10 Available Backset:55/60,disance:72/85 Function(Optionals): Normal Entrance/Passage/Classroom...(More detail,please cintact US).