In standard one-way action, dead bolt thrown or withdrawn by key from either side and withdrawn by lever or turn knob from inside Two way action thrown or withdrawn by key or handle from either side. Deadbolt is brass with two hardened steel rollers and the throw is 13mm. One way action as standard and two way available on request. The measurements are as follows: 76mm(A) lock comes with 57mm(B) backset and 52mm(C) centres, 101mm(A) lock comes with 82mm(B) backset and 52mm(C) centres