Blackstone Bike lock is an ultra-strong independently approved 14mm shackle lock with hardened steel construction. As well as being an extremely secure lock it has a built-in alarm triggered by movement sensors. It can also be lock without setting the alarm. This bike lock comes with a 5 feet premium steel cable and the whole diameter of the line is 1 inch thick and it will provide your bike with greater locking flexibility and better protection. There are two ways to lock one is to lock with alarm and the other is to lock without alarm. The Blackstone offers a key replacement service. When you buy your Blackstone bike lock note down the number attached to the keys on a metal tag. Please keep this in a safe place and then it will be possible to get a new key made up for you when you lose all your keys.