A premium 3 key cylinder is a type of lock that uses a patented mechanism to prevent unauthorized key duplication. It is designed to provide high security and functionality for master key systems. It has anti-pick pins, drill protection, and a BSI Kitemark certification Specification : Brass Computerized 5 Key ensure high Security, 7 Pin mechanism to obtain wide key combination, Long Life, Maintenance Free, Can be fitted in any Euro Standard Mortice Body.