The Mag-Tank takes a new twist on top tube bags. Instead of a zippered opening, access to the bag is by contoured top flap held in place by a magnetic buckle with mechanical engagement. It will not unintentionally open and spill your gear. Hook and loop straps hold the bag securely to the stem and top tube. Two sets of mounting holes on bag bottom to allow bolt-on attachment to top tube First set of mounting holes spaced at 76 mm (+/- 2 mm) from the front of the bag Second set of mounting holes spaced at 100 mm (+/- 2 mm) from the front of the bag Distance between mounting holes is 64 mm (standard water bottle cage spacing)