Yale Locks P85 Deadlocking Nightlatch 40mm Backset DMG Finish VisiThe Yale 85 series deadlocking standard nightlatch security locks are some of the most widely used front door latches. They are key operated from the outside and lever handle operated from the inside. The latch automatically deadlocks on closing the door and the snib function (bolt hold back button) enables the latch to be held back. The inside handle can also be deadlocked by a reverse turn of the key in the cylinder giving additional security (when