Keep your bike safe! OnGuard's Bulldog ATB boasts 1/2-inch hardened-steel construction and OnGuard's stout X2 double-bolt lock that resists picking, drilling, bumping, and pulling for serious protection. It also features a wide shackle, making it ideal for bigger framed bikes. And thanks to the included mounting bracket you can bring the Bulldog ATB along for every ride. This great U-lock also comes with five keys, including OnGuard's Microlight key which has a built-in light.