The Master Lock 17/8 in. Magnum C Steel Padlocks with Shackle feature a 1-7/8 in. (48mm) wide laminated steel body for maximum strength and reliability, and is surrounded by stainless steel and zinc outer components for weather resistance. The Rust-Oleum® Certified protection provides a lifetime guarantee against rusting on the lock body; and covered lock body, keyway, and shackle seals offer additional weather protection. The 5/16 in. (8mm) diameter octagonal shackle is 1-1/2 in. (38mm) long and made of Tough-Cut™ boron-carbide, 50% harder than hardened steel, offering maximum resistance to cutting and sawing. The 4-pin cylinder prevents picking and the dual locking ball bearings provide maximum resistance against prying and hammering. The Lifetime Guarantee provides peace of mind from a brand you can trust.