Operated from both sides of the door by a key. High durability cylinder rings against pulling, twisting and sawing. This product has ABLOY PROTEC²-lock system. ABLOY PROTEC²is a factory level locking solution. Every key is carefully controlled and is only made at Abloy Oy's factory. The keys have a patented sliding element that increases key security. One key fits several locks. How many locks a single key opens and who has access to what, can be accurately controlled.