Sport-T 4 lt Tanklock tank bag
The TankLock system for tank bags eliminates the use of straps or magnets previously used to fasten the bag to the bike. You simply install the specific ring on the tank cap, then attach the bag by alligning it to the ring and pressing lightly until you hear a "click." Equally easy is the removal of the bag, you just pull the red lever located in the base.
Requires bike specific flange to mount (see list under resource downloads below).