Master Lock® Safety Padlock, Rectangular, Die Cast Body, 5/16 in Shackle Diameter, 1 in Shackle Height, 1 in Shackle Width, Hardened Steel Shackle, 2 in Body Width, 1 in Body Thickness, Black. Master Lock® 178D Rectangular Safety Padlock, 5/16 in Shackle, Die Cast Body, Black