The Arrow Lock BM11-LB Lock Body is a part for the BM11 Apartment Lock Series. It has a latchbolt that is operated on either side by a lever, except when the outside lever is locked by stopworks, or when the deadbolt is projected. The deadbolt is operated by a key outside and a turnpiece inside. If you turn the inside lever, it will retract both the latchbolt and deadbolt simultaneously.