ADAMS RITE deadlatch mechanism: screw-in cylinder (supplied separately); backsets 22mm,24mm,28mm,and 38mm; Aluminum finish forend; Reversible latchbolt withdrawn from either side by key or turn using any standard screw in cylinder (Mul-t-lock) or thumbturn wuth cam or 4590 paddle handle (with 4580 cam plug), To operate holdback facility push in bolt and secure by reverse turn of the key.