The Yale 88 Standard nightlatch security lock is 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. Supplied with 1109 Cylnder in brass or chrome finish. The 88 series security nightlatches have a 60mm backset, this is the measurement from the edge of the door to the centre of the keyhole. Locks with a 40mm backset are normally used where there is restricted space, such as on a narrow glass panelled door.