The Master Lock Magnum® No. M50XD Discus Padlock features a 3-1/8in (79mm) wide stainless steel body for maximum strength, reliability and corrosion resistance. The fully shrouded design minimizes shackle exposure and protects against bolt cutter attacks. The 7/16in (11mm) diameter octagonal shackle is 11/16in (17mm) 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 covered keyway offers maximum weather protection, and reinforced body bumper protects against scratches. The Lifetime Guarantee provides peace of mind from a brand you can trust.