Master Lock Armored Trailer Lock with Shackle Guard. 1-9/16" wide laminated steel case. 4-pin tumbler. Revolving case-hardened shackle-guard. 4-pin cylinder helps prevent picking. Rust-resistant nickel-plated and armor. Shackle clearance, vertical 15/16", horizontal 7/16". Comes with 2 brass keys. Dual locking levers provide extra pry resistance. Resists saws and bolt cutters. For use with cables, chains or hasps. For guarding trailer on or off vehicle.