Helmet lock with T Bar, cable and combination lock The Helmetlok can be used to lock your helmet to your bike. No need to use the T Bar Extension if you have a "D" ring on your helmet, but you may like to use it if your helmet has a quick release buckle. The extension slips into the "quick release" buckle and the Helmetlok fits through the hole and onto your bike! Use the cable if you wish to secure your jacket, bag or a second helmet to your bike. The ORIGINAL Helmetlok is a secure lock, once you put in your code, it cannot be changed unless you use your original code to change the numbers.