Streamlined and Compact Design: 47 x 20 x 10CM in size. Ergonomically fits for your shoulders, chest, and waist. 3 straps are all adjustable for reducing bounce. mesh back speeds up air-flow and makes your back cool. Foam padded shoulder straps are extremely comfortable. Practical Functions: 1 main pocket fits up to 3L water reservoir with either large or small opening. 2 external pockets for storing personal belongings wallet, gadget, towel, phone, keys. The MOLLE system allows you to carry more items. Professional 3L Hydration Bladder: Quick release valve allows you to refill water without connecting hose. Large opening is easy to clean and add . 360 degrees rotatable mouthpiece allows for easy drinking. Shut On/Off valve helps to adjust water flow. Middle baffle keeps the bladder flat and makes it easier to place into the backpack. Versatility: Frees your hands while drinking, this hydration pack is your perfect choice for short trip, camping, bike riding, walking, mountaineering, kayaking, skiing, snowboarding. A decent Holiday Gift for families and friends who love outdoor sports. Color: black + green Material: Oxford cloth+EVA Cleaning: Before the first use, fill the bladder with dish soap or baking soda and warm water, run the liquid through the tube and mouthpiece, and then let them sit for 2 hours. Rinse them all several times with clean water and let them air dry. Storage: Empty the water, rinse clean and make sure it is completely dry before storing. Main pocket can hold either large or small opening water bladder, compatible with most of bladders on the market. Two external pockets are used to place personal items T-shirt, toiletries etc. The MOLLE suspension system expands to attach more items. Shoulder, chest and waist straps can all be adjusted to your comfortable size, keep the pack snug to your back. Three breathable mesh pads at the backside make ra