The Kryptonite Kryptolok ATB U-Lock features a 12. 7 mm hardened performance steel shackle with a double deadbolt anti-rotation design that resists bolt cutters and twisting leverage attacks. The locks disc-style cylinder with center keyway is protected by a vinyl coating and is pick and drill resistant. The keyway also features a sliding dust cover to protect the cylinder from dirt and debris when not in use. It includes two stainless steel keys with an ergonomic design to reduce torque and keep them from bending or breaking. Rated at a 6 / 10 on our security scale, the Kryptolok ATB is good for quick stops in a metropolitan area, a couple hours in the suburbs, or all day & overnight in rural areas. It also includes our patented FlexFrame-U Bracket providing convenient multi-location U-Lock transport. The combination of these great features and our support programs including Key Safe, Anti-Theft Protection, and Lifetime make Kryptonite Bicycle Locks the best choice for protecting what you value.