The British Standard High Security Nightlatch Door Lock is a high security door lock with a classic and robust design. Available in both40mm and 60mmbackset making it an ideal product to replace most existing front door locks and is ideally suited for panelled doors. Particularly suitable for glass panelled doors, as the ergonomic internal locking handle, which can be deadlocked by an anti-clockwise turn of the key from the inside, offers additional security against forced entry. The main bolt is “automatically” deadlocked into the striker, when the door is closed, preventing it from being retracted by a credit card. Designed with a 20mm bolt throw for even greater security and strength. A simple snib button enables the latch to be held in the withdrawn position (only), allowing the door to be accessible without operating the handle.