The union 5 lever bs mortice sash lock 67mm is ideal for timber doors hinged on the left or right and the keys are suitable for doors up to 54mm thick the 20mm deadbolt is locked or unlocked by the key from either side for secure positive deadlocking and additional resistance against attack this lock features an anti pick anti saw and anti drill security chamfered bolt design that increases the performance of the lock under side load testing the chamfer of the bolt also makes drilling atta