B89 Deadlocking Security Night Latch Lock Enamel 60Mm Backset

Snib to deadlock or hold back the latch. During that process you will be issued with an RMA number. Deadlocked by the snib button internally, making the lock inoperable by key or handle. Inside handle can be deadlocked by a reverse turn of the key in the outside cylinder after closing the door.

eBay