The Yale PM562 British Standard 5 lever mortice deadlocks offer a very high level of security and are suitable for use on external timber doors. The deadbolt is locked or unlocked by key from either side. The PM562 series lock are recommended by insurance companies, kitemarked to BS3621: 2007. These deadlocks also have a 20mm anti-saw deadbolt, an anti-drill case and have a 15 year guarantee. A deadlock has a single deadbolt which is locked or unlocked and locked by means of a key from either side, whereas, a sashlock has both a deadbolt and a latch which is operated from either side by a lever handles. The security level of mortice deadlocks or sashlocks ranges from 2-5 levers. The higher the number of levers the more secure the lock is.