NOTE: HYDRATION/WATER BLADDER ONLY! NO BAG INCLUDED! MILITARY GRADE QUALITY HYDRATION BLADDER : The 2 liter hydration bladder and 17.8'' x 6.9'' perfect size is compatible with most sizes hydration backpacks. 2 liter capacity is almost fit for all sports. It conveniently quick and easy to have a drink. PREMIUM QUALITY:The military grade hydration water bladder is thick, BPA free, SGS certified. Food grade EVA material plus TPU drinking tube make the whole water bladder taste free. The water bladder passed pneumatic pressure test, double sealing side technique has greatly improved durability. FREE VALUABLE PACK SPACE & LIGHTWEIGHT:Since hydration bladder is stored in the backpacks , no extra space is used. Besides this, our hydration bladder is very light just about 4.2oz. The big opening makes for easy filling / pouring of water. Also can put some big ice cubes into water bladder to keep water cool. EASY TO STAY HYDRATED : Because of the drinking tube attached to hydration bladders, remaining hydrated is now simple. Simply bite the mouthpiece to suck water. Soft mouthpiece with easily accessible ON/OFF valve prevents leakage. It also has a cover to keep dirt out. Conveniently control the water flow by biting, when not bite, the water will not leak out.