Padlock - Hardened Steel Shackle - Extra protection against hacksaw & cropping attacks. Double Bolted Locking Mechanism - Extra strength to resist torsion & pull attacks. Stainless Steel Body - Maximum resistance against corrosion. Drill resistant keyway - protects the cylinder against drill attack. Hasp - Concealed hinge pins - prevents 'knock through' attack. Zinc plated finish - extra protection against corrosion. 10 year guarantee.