The 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 deadlocked in this manner the latch cannot be opened from the inside only from the outside with the key). It comes supplied with 1109 cylinder. The 85 series security nightlatches have a 40 mm backset--this is the measurement from the edge of the door to the centre of the keyhole. Locks with a 40 mm backset are normally used where there is restricted space, such as on a narrow glass panelled door. This Yale P85DMGPB has a hardened case finish in dark metallic grey and the cylinder is finished in polished brass. The lock is covered by a 2 year guarantee and has a high security rating.At Yale, they have been taking care of people and their favourite things all over the world for over 200 years. Like your great-great-great grandparents before you, you can be secure in the knowledge that fitting Yale alarms or Yale locks to your doors and windows means complete peace of mind and full protection for your family and property. Yale is one of the oldest international brands in the world and probably the best-known name in the locking industry. The Yale history captures major innovations that have marked the evolution not just of Yale, but of the entire locking industry.