An automatically mortice deadlocking lock for narrow profile doors ideal for use with wooden doors, which can be opened by a key from either side or by a thumbturn from the inside.
The function is determined by the sliding snib on the forend. Sliding snib is released only when turning the key.
UP position = self regulating deadlock; Opened by key from either side, or by thumb–turn from inside
MIDDLE position = lock is closed and works also with handles
DOWN position = latch bolt is retained inside the lock case
Strike plate 4613 included