The hydration backpack aligns your back while gently protecting your muscles. The ventilated mesh cover maintains air circulation, preventing discomfort from accumulated heat. Experience excellent breathability during your outdoor activities.Features:Mesh shoulder straps for maximum breathability and comfort.Made from tear-resistant and waterproof nylon fabric for extremely light weight and durability.The elastic front pocket and zippered pocket on the shoulder strap keep your essentials like cell phone and energy gel close at hand. Reflective strips increase visibility and safety.Specially designed for road cycling, running, hiking, and more, the compact and stable construction minimizes wind resistance. Specifications:Material: 90% nylon + 10% spandexColor: Black and Blue/ Black and White/ Light Grey and Dark Blue/ Light Grey and Orange (optional)Capacity: 5LSize: 35*18cm/ 13.8*7.1inWeight: 140g/ 4.9ozPackage List:1 * Hydration Vest Backpack1 * Water Bladder