TIPS FOR USEfter filled the Hydration Bladder,please screw the cover closely.The backpack is customized for the water bag,if the water bag filled with water,backpack only have a few space to put other stuffs, when you used,the squeeze from your back will accelerate the water bag damage.So,please don't fill the water bag fully.Please don't put water bag and sharp items together,such as keys. HAND FREEIf the Hydration Bladder have problem at your first time test ,please send us a message for help,with pictures are better,we will fix your problem quickly. Hands-free hydration hose with bite valve, gently biting the valve to open up the flow of water. Rucksack Backpacks CONVENIENT FOR USEThe Hydration Bladder With a pouch on the back, easy to carry your phone, keys and some small tools. Backpack for men, women, and youth; Low-profile athletic cut with full adjustment fits all frames comfortably; Comfort-taped straps mesh covering means you can wear this pack for hours WIDELY USEHands-free hydration hose with bite valve, gently biting the valve to open up the flow of water.Great partner of running, hiking, Riding and other Outdoor sport. Fully removable 3 liter (100 ounce) water bladder.A great backpack for men, women and kid to stay hydrated DURABLE AND REUSABLEConstructed with waterproof 800D Nylon material, the backpack is wearable and durable.