Item Type: Water BackpackMaterial: Oxford Cloth, NylonSize: Approx. 43 x 22.5cm / 16.9 x 8.9in(The Size is Measured Manually, There May Be Small Deviation)1Made of high quality Oxford cloth and nylon waterproof material, it is light and wear resistant, and the mesh back is comfortable and breathable. 2Can prevent sweating and provide comfort. this backpack is the best choice for outdoor sports, including cycling, running, hiking or camping. 3Adjustable shoulder straps and chest straps make your backpack fit perfectly, will not burden your back during running, prevent moving, 4The wide mesh shoulder strap helps to reduce the burden on the shoulders and is perfect for exploring nature and outdoor activities. 5The running backpack is designed with double zippers and 3 pockets for easy storage and provides maximum convenience for sports enthusiasts.