Disc padlock from Master Lock. Corrosion-resistant stainless steel disc lock. Extra hard, cut-resistant boron carbide shackle with 4-pin cylinder, dual ball bearing locking and covered keyway. Supplied with 4 keys. Disc protects shackle offering higher security. Pry-Resistant 4-Pin Tumbler Locking Mechanism Stainless Steel Body Octagonal Boron Carbide Shackle Suitable for Outdoor Use Pry-Resistant 4-Pin Tumbler Locking Mechanism Stainless Steel Body Octagonal Boron Carbide Shackle Suitable for Outdoor Use