YALE 85 & 89 Deadlocking NightlatchThe Yale P85 & P89 are deadlocking nightlatches suitable for left & right handed, and inward opening doors with a thickness of up to 57mm. The locks offer high security, are covered by a 2 year guarantee and are supplied with 2 keys. Inside handle can be deadlocked by a reverse turn of the key in the outside cylinder after closing the door Snib to deadlock or hold back the latch Deadlocked by the snib button internally, making the lock inoperable by