This padlock features a laminated steel body that is surrounded by stainless steel and zinc outer components for weather resistance, maximum strength, and reliability. The Rust-Oleum® certified protection provides a lifetime guarantee against rusting on the lock body. The covered lock body, keyway, and shackle seals offer additional weather protection. The 5/16-inch (8mm) diameter octagonal shackle is 1-1/2 inches (38mm) long and made of Tough-Cut™ boron-carbide that is 50% harder than hardened steel, offering maximum resistance to cutting and sawing. The four-pin cylinder prevents picking, and the dual locking ball bearings provide maximum resistance against prying and hammering. A lifetime guarantee provides peace of mind from a brand you can trust.