The Bell Rampage 400 Chain Lock offers the strength of a u-lock with the portability of a cable lock. At 3-feet long, the chain can wrap through the frame and front wheel, securing the most vulnerable points on a bicycle. Heavy-duty 6mm diameter hardened steel links provide meaningful protection against thieves while the woven nylon sleeve prevents damage to a bicycle's paint. The Rampage 400 comes with two standard keys that can be registered after purchase online, see packaging instructions on how to register. In the event registered keys are lost, Bell will send replacements at no charge. An independent lab has rated the security of this lock a 3 on a 5 point scale. Perfect for locking bikes or other large items in low to medium crime areas.