This is the Giant SureLock Protector 1 DT U-Lock . Features: X4P Quattro bolt locking mechanism provides unequaled strength by locking cross bar to shackle Massive 14mm (0.55") ultra-hardened steel shackle provides maximum cut-resistance Zinc caps offer more protection against hitting attacks M-Key cylinder is more reliable and user-friendly than ever before, prevents key from turning before being fully inserted into the cylinder All-tube QR mounting bracket included-fits 24-40mm tubes Micro-light key projects a highly focused white light beam Integrated dust cover protects the cylinder Includes 3 keys (1 micro-light and 2 extra keys) Note on Bike Locks: Bike locks provide deterrent to bike theft, however no lock is theft proof. Please research both your area you plan to lock the bike, amount of time and time of day, and then which lock best suits your specific needs. Remember that locks may seem expensive, but a new bike is always more.