Five Lever Mortise Deadlocks conforming to British Standard number BS3621: 1998 for Thief Resistant Locks. This is a high security door lock that has been rigorously tested for burglar resistance. This type of door lock has a single 'dead' bolt that is locked and unlocked with a key. It is embedded in the door for extra strength, providing exceptional security and is specified by many insurance companies.
It offers excellent protection against all common forms of attack including lock picking, force, drilling, manipulation and hacksaw. The 2 and 3 Lever Door Locks UK are not recommended for use on exterior doors. A Sash lock is like a deadlock, but also has a built in latch, which can be opened by handles. These locks are normally used on internal doors, so that the door can be latched closed, but it can also be locked for security