The Union 3K74 series British standard 5 Lever Mortice rollerbolt sashlocks are suitable for use on timber doors hinged on the left or right and are also suitable for use on doors up to 50mm thick. The lock has a deadbolt operation and is locked or unlocked by key from either side with the latch bolt being withdrawn by a lever handle from either side. It has force resistant, anti drill, anti-pick and anti-saw security features and is available with square forend and striking plate with a 14mm bolt throw. They are also pierced to accept bolt through furniture. The 3K74E series locks are recommended by insurance companies, kitemarked to BS3621: 2007 (British Standard) and has been approved by the police Secured by Design initiative. They are also covered by a 25 Year guarantee. Deadbolt: Brass, with hardened steel rollersLatch Bolt: Roller bolt (non handed)Follower: Sintered Iron, 8mm squareKeys supplied: Standard differ supplied with 2 keys. For locks to pass please specify number of keys required.Key Blank Number: B-K722 (standard)Cut Key Number: B-5LCNB Not suitable for master keyingRebate Kit B-3K74R (13mm, 19mm and 25mm) EN1634-1 assessed for use on 60 minute timber fire doors.Visi packed.Finish: Polished Brass FinishForend: BrassBox Strike Assembly: Painted to match forendCase Finish: Silver powder coatCase Size: 80mm x 108mm (3in)BackSet: 53mm This is the measurement from the edge of the door to the centre of the keyhole.Centres: 57mm This is the measurement from the centre of the follower, which operates the handles, to the centre of the keyhole. In the UK this is commonly 57mm.