Ortlieb's clever lock helps you secure a QL2/2.1/2.2 pannier onto your rear rack. It's got awesome tool-free installation, and is quick and easy to lock and unlock with one key. Compatible up to 16 mm tube diameter, and when combined with E124/E125 Cable Lock Anti-theft device, it's also suitable for securing quick access to the contents of a roller bag or securing the helmet.