The Master Lock Magnum® No. M176XDLH Solid Body Padlock features a 2in (51mm) wide zinc die-cast body for strength and reliability. The 3/8in (10mm) 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 roller pin cylinder provides maximum pick and pry resistance. The dial cover offers superior weather protection, and reinforced body bumper protects against scratches. The lock includes set your own combination and the added convenience of a back up key. The Lifetime Guarantee provides peace of mind from a brand you can trust.