1.Accurate Leakproof : Whole body edge of this 2L bladder adopts a double soldering sealing side quilting design to withstand a large degree of squeezing. One end of the water tube is self-sealing mouthpiece and another is automatic locking connection socket whose waterproof ring has been shaped and adjusted tightly. When the water pipe is inserted, it can be auto-locked fast and will not loose. 2. PREMIUM QUALITYBPA free, 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. 3.FREE VALUABLE PACK SPACE & LIGHTWEIGHTSince hydration bladder is stored in the backpacks , no extra space is used. Besides this. The big opening makes for easy filling / pouring of water. Also can put some big ice cubes into water bladder to keep water cool. 4.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. 5.You can apply backpack hydration bladder for outdoor activities: hiking, running, bicycling, skiing, riding, camping, cycling, climbing, etc. It is a must have for sports enthusiast and an ideal gift choice.