ABUS 83AL/40-300 S2 Schlage Rekeyable Padlock Aluminum Body with 1.5-Inch Shackle, Blue Zero-Bitted Extreme corrosion resistant plating Shackle made from hardened steel Double bolted: both sides of the shackle are secured by bolts or balls- increased protection against attacks and manipulation Key retaining: a key is needed for locking, Lock retains key until locked