Revelate Design took the beloved Mag-Tank and made a version compatible with top tube bolt bosses. The Mag-Tank takes a new twist on top tube bags. Instead of a zippered opening, access to the bag is by a smartly contoured top flap held in place by a magnetic buckle with mechanical engagement (read - the magnet aids in closure, while load is placed on a connection). Unlike a conventional magnetic closure, the Mag-Tank will not unintentionally open when you end up in the trees with your bike upside down. You can easily open the bag one handed by pulling outward on the cord loop and you have access to the whole top of the bag. To close, just flick the flap down and the buckle self-engages! Compared to our standard Gas Tank, the Mag-Tank is just a hair smaller to prevent leg movement from hitting the edge of the flap opening.