iPod, iPhone Full Tilt Classic bottle hydration waistpack carrier by Amphipod Black Bottle Pack of the Year award-winner 20-ounce Hydraform Bottle designed for easy retrieval and replacement of bottle Expandable stretch-mesh, zippered pocket holds gels, keys, and other essentials Cool and vented AirFlow Mesh back panel Ergonomically sculpted low profile design hugs lumbar to minimize bounce / slosh