The top zone bag is a great little addition to your bike packing, commuting, MTB, road, or Tri rig. It goes on easily to the top tube with it's hook and loop closure system and has a main storage compartment plus two additional side pockets. It's 1.1 Liters, or 67 cubic inches, and is a perfect place to store snacks, keys, money, an extra tube, and pretty much any other smaller personal item you may need along your ride.
