The Master Lock Magnum M1XT Laminated Padlocks with Keys feature a 1-3/4 in. (44 mm) wide laminated steel body for maximum strength and reliability, and is surrounded by stainless steel and zinc outer components for weather resistance. The 5/16 in. (8 mm) diameter octagonal shackle is 1 in. (25 mm) 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 know and can trust.