The Master Lock 1-3/4 in. Magnum Steel Padlocks with Shackle feature a 1-3/4in (44mm) wide laminated steel body for maximum strength and reliability, and is surrounded by stainless steel and zinc outer components for weather resistance. The 5/16in (8mm) diameter octagonal shackle is 2in (51mm) 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.