Simplex LP1010 (without key override) Virtually indestructible push button exit lock that will interface with leading brands of panic/crash bars.  The LP1000 is from the Simplex line made by security solutions leader, Kaba Ilco, so you know it will last.  The Simplex LP1000 series is a heavy-duty stand-alone security lock that is highly weather resistant.  Entry is gained via a 1 to 5 digit code that is sequential.  Vandal resistant, the Simplex series of keyless locks have found widespread acceptance in high-traffic commercial, institutional, and government buildings.