Kryptonite's Keeper 12 Long Shackle U-Lock is like a tough nut: you just can't crack it. Thanks to the 12mm hardened steel shackle that resists cutting and leverage attacks, you get peace of mind while you run into the grocery store or lock up outside the coffee shop. The shackle connects to the disc-style cylinder for exceptional security, and it all sits in the click-style transportation bracket so it stays stable during transport. To top it all off, you get a reinforced collar over the keyway for added protection, not to mention Kryptonite's Anti-Theft Protection offer. The lock measures 4 x 11.5-inches for plenty of locking clearance.