Features: 3L BPA FREE HYDRATION WATER BLADDER & HIGH-QUALITY MATERIAL --- tough and water-resistant high-density 600D polyester fabric, construction rope, high-quality buckle. 8.46"x9.45"x18.7" in size. TWO FRONT LARGE POCKETS & MOLLE SYSTEM --- Two Front pockets can hold your wallet, keys, phone, towel, or small items. There are net bags and a key hook in one of the pockets, which can be used to classify and sort out items. The Molle system can expand any extra gear which you like. EASY ACCESS TO DRINK --- Double guarantee- a switch valve and a cover cap. Don’t need to worry about the leak. Hands-free hydration hose with suck mouthpiece, gently biting to get the liquid to flow. With a wide screw cap, you can add ice cubes to keep your drink even colder. comes with a whistle buckle for emergency. ADJUSTABLE CHEST AND WAIST STRAPS --- Shoulder straps filled with breathable air cushion helped breathable perspiration and maintain a comfortable state. Adjustable chest and waist straps secure the pack in place to eliminate any bounce or rubbing. Built-in fixed buckles help the bladder fixed in position, no more shaking. soft, breathable foam panels on the back ensure your back stays cool and dry. The waist size is up to 41.73inch. OCCASIONS --- The lightweight and streamlined design with a 3-liter water bladder won’t weigh you down. Ideal for hiking, running, biking, walking, all-mountain riding, and mountain biking. NOTE: THE BLADDER HAS BEEN UPGRADED. The new version works better. If any questions, just feel free to contact us.