Dual-Armor protection: laminated steel core for strength surrounded by stainless steel & zinc outer components for weather resistance. Tough-Cut octagonal boron-carbide shackle is 50% harder than hardened steel. Dual ball bearing locking for maximum pry resistance. Reinforced body bumper for scratch resistance. 4-pin cylinder for increased pick resistance. All 4 locks in blister pack will have same key. Each case of 6 will have different keying. Lifetime guarantee.