Latchbolt operated by lever handle from either side. Deadbolt operated by key from either side using a double cylinder (not supplied) or by key outside and thumb turn inside using a cylinder thumb with turn(not supplied).Pierced to accept 20mm and 38mm centre bolt through fixing escutcheons and 38mm horizontally and diagonally opposed bolt through fixing furniture. Latchbolt is brass and reversible; projection is 12mm. Deadbolt is also brass with two hardened steel rollers and the throw is 14mm. The measurements are as follows: 76mm(A) lock comes with 57mm(B) backset and 72mm(C) centres, 101mm(A) lock comes with 82mm(B) backset and 72mm(C) centres