For maximum strength and durability, the lock body is made from solid hardened steel and the shackle is made of hardened boron alloy steel. Designed to meet the CEN European Standards, SQUIRE Stronghold® Bullit range conforms to BS EN12320 grades 3 and 4 with an approved cylinder. Solid hardened steel lock body Rekeyable 5 pin cylinder - 1500 key differs Hardened boron alloy steel shackle Electrophoretic finish - excellent corrosion resistance.