The lock (not included) is guided through a waterproof tube that runs through the visor opening and protrudes from the bottom of the helmet, allowing you to attach it to your bike. The simplest lock you can use is a reinforced cable lock, but you can also use a chain lock or a regular cable lock. This provides a secure way to leave your helmet with your bike and protects it from the elements. It is suitable for chain and cable locks and features a convenient hook-and-loop hanger to keep your helmet off the wet ground.