The fortress 5 lever british standard bs deadbolt mortice door lock is a high security deadlock conforming to the bs 36212007 meets the exacting demands of insurance companies and the police higher security and strength are delivered by a 20mm bolt throw in every lock designed with hardened steel plates to resist drilling and two hardened steel plates in the deadbolt to resist hacksawing the keys have 1000 variations for added security all steel levers have false notching to resist loc