[【Ergonomic Design】Body-mapped and super-breathable materials for maximum comfort and ventilation. Ergonomic mesh-covered padding allowing air circulation for a cool comfortable fit and helping absorb impact in a crash. The adjustable sternum straps and lower lumbar straps in compressing and stabilizing loads for optimal carry and fit. 【Lightweight and Adjustable】: Running water bag backpack size: 14.6 x 7.9 x 2.4 inches (37 x 20 x 6 cm). This hydration backpack is made of high quality nylon material which is waterproof tear and fade resistant. The lightweight zipper is reliable and durable perfect for training and those who like to travel long distances. 【Incredible Storage】The bicycle backpack can carry a lot of water. This hydration backpack has a main compartment and plenty of room for all your essentials including cell phones flashlights hydration packs water bottles clothing hiking accessories and more. Great for travel. 【Adjustable Shoulder Strap for Better Stability】The shoulder strap fits the size of the chest and waist so that the backpack stays firmly on your body. This prevents moving of objects inside and improves performance. 【MULTI-PURPOSE】Our water bladder hiking backpack is suitable for hiking running mountain biking cycling mountain climbing and other occasions. This running hydration vest is a great gift for family and friends. The main backpack for outdoor sports the flower of vitality was born here.]