High quality water bag: Hydration bladder is made of high quality and safe food grade PEVA material. The outdoor water bag is double sealed on the side and has also passed the pressure test to prevent leakage, which ensures stability and safety during use. Large opening design: our outdoor hydration backpack has a large opening with screw cap for easy filling, unscrewing and tightening. It is also wide so the bottle brush can easily access the inside of the hydration bladder for easy cleaning. You can also put ice cubes through the large opening to drink ice water and ice drinks on the hike. Water bag can be used at temperatures from -20C to and50C. Practical design: the drinking bag has a soft teething mouthpiece with a shut-off valve that is designed according to ergonomic principles, and the water flow is faster, so you can rehydrate quickly and easily. The water flow will bite comfortably by the controlled bite, and the water does not leak when not bite, comes with dust protection. The dust cover keeps the mouthpiece clean and hygienic. Small and Lightweight: These hydration packs are specially designed for road cycling or running or hiking, with a size of only 34 x 17 cm and a capacity of 2 litres, lightweight and portable, making your back feel light and stable, reducing wind resistance and keeping your body at peak performance. Multifunctional: this 2 litre hydration bladder is compatible with most hydration backpacks. Free your hands when drinking water. Perfect for your outdoor activities such as running, cycling, climbing, hiking etc., it is a must-have for sports enthusiasts.