The Yale PM322 3 Lever Mortice Deadlock offers a standard level of security for internal timber doors. This deadlock features a deadbolt that can be locked or unlocked by key from either side. It also includes a 13mm anti-saw deadbolt and comes with a 10-year guarantee. Deadlocks secure with a single deadbolt operated by a key from both sides, unlike sashlocks which also have a lever-operated latch. Security for mortice locks is rated from 2 to 5 levers, with higher numbers indicating greater security.