The lightweight hydration pack is made of lightweight and breathable mesh fabric, 3D breathable padding on the backrest improves breathability, soft backrest prevents chafing on the skin while exercising, elastic chest strap with safety whistle and adjustable to the right position shoulder straps provide a better fit for your back while exercising and reduces bouncing and loading during cycling, running, hiking, and mountaineering exercises.Multi-functional water bag backpack is suitable for any occasions, small lightweight backpack with insulated heat preservation effect is a wonderful choice for commuting, sports, meets all types of people, Water backpack for hiking a novel gift can be given to family and friends.