The Guardian Entrance door knob set is designed to replace Weiser door knobs. Weiser door knobs were commonly used in the 1970's and 80's. Weiser use a very specific latch system which requires a large portion of the door to be removed. This can mean it is very difficult to find replacement knobs without reconstructing and filling your doors. The Entrance set uses a lock and key and is accessed from inside or outside via keys supplied (2no.)