The SECO-LARM Mechanical Keypad Door Lock provides secure locking while avoiding the hassle and cost of dealing with providing, duplicating, or replacing keys. Unlike keyed locks, the lock code can be easily changed by the user at any time. The code is not sequential, so the code letters/digits can be entered in any order. Since it is completely mechanical, there is no need to run wires from a power supply or replace batteries. The inside handle always operates to allow safe egress in an emergency.