The QL3 attachment system mounts to the right or left side of your rack. This component is fully adjustable both for heal clearance and angle of your bag. Ortlieb's commuter bags that utilize the QL3 system, the Ortlieb Downtown and Ortlieb Office series, now have a much smooth backing plate making them more comfortable to carry.
The upper mounting clips have an auto lock so the bag stays securely mounted to the rack, simply pull the handle up to unlock the clips. The QL2 system is not compatible with the QL3 system and cannot be modified to accept the new components.