The King Enterprises audio detector is designed for use in bank vaults constructed to comply with the 1968 Bank Protection Act, and current UL rated class 1, 2, 3 concrete based modular vaults. It can be mounted on the ceiling or suspended from ceiling tile inside the vault. One unit can be centered on an area no larger than 20 x 20. Additional units can be mounted in larger vaults. If a vault has partitioned walls, install one unit per partitioned area. Current draw in a non-alarm condition is 27ma, alarm condition is 11ma.