The Union StrongBOLT BS 5 Lever 3" Mortice Deadlock in Stainless Steel has keyhole protection, hardened steel pins and a chamfered bolt for greater anti-pick, anti-saw and anti-drill security features resulting in better attack resistance. This deadlock is easily retro-fittable into many existing UK mortice locks and is suitable for doors up to 54mm thick. Supplied with a radius plastic splinter guard, box strike and anti rattle strike.