A flexible flask (with a bite valve) that shrinks as you hydrate and the contents decrease. It won't interfere with your exercise because the drink doesn't slosh around inside. Capacity: 250ML Will be shipped in simple packaging. teton RIDGE MOUNTAIN GEAR Ridge Mountain Gear Yamato Michi (Mountain and Road) Ogawand Ogawand Hyperlitemountaingear Hyperlite Mountain Gear hikersdepot Hikers Depot Gossamergear Gossamer Gear Atelierbluebottle Atelier Blue Bottle Sixmoondesigns Six Moon Designs Moonlightgear Moonlight Gear Locusgear Locus Gear Mountainlaureldesigns MLD Mountain Laurel Designs Zpacks ZimmerBuilt ZimmerBuilt rawlowmountainworks RawLow Mountain Works answer4 Yamato Michi (Mountain and Road) houdini Mountain Martial Arts MountainMartialArts Houdini TetonBros Teton Bros. MAMMUT Norrona norrona tilak ROJK The North Face northface Arc'teryx ARC'TERYX axesquin Axesquin