Traditional high security Yale Nightlatch approved to British Standard BS 8621:2007 and Police Secure by Design Automatic deadlock locks when closing the door for instant security and latch can be held back temporarily with snib button High security TS007 1 star Rim Cylinder with reinforced exterior for anti-drill protection and components designed to resist known attack methods Internal nightlatch handle can be locked from the inside with a key, ideal for use with wooden doors with glazed panels Supplied with 2 standard Yale keys and fixing pack for easy installation Anti-card slip protection, prevents your lock from being vulnerable to this technique that only requires a card sized piece of plastic What to consider when buying a nightlatch. Which size do I need? Yale Nightlatches come in two different backset sizes that fit different door types. Make sure you measure the door before you purchase one. The backset on a night latch is the distance from the centre of the keyhole to the edge of your door. What's in the box? 1x Yale BS1 Maximum Security Nightlatch 60mm - Dark Metal Grey Casing, Brass Cylinder 1x Rim Cylinder Fixing Pack 2x Keys