The GIVI Tanklock System eliminates the need for straps & magnets & is specially suited to motorcycles with a plastic tank. A sturdy polypropylene retaining ring is mounted to the fuel cap frame on the tank & the bag is locked in position by the patented quick-release mechanism. Operation is extremely quick: just drop the bag in place to lock it & pull the red spring-loaded tab to release it. The fuel cap remains easily accessible to fill-up at the fuel station & most bags can be repositioned by moving the whole mount back or forward on the base plate.