1、Durably made with anti-tear polyester fabric, water-resistant and lightweight. 2、Breathable shoulder strap and back for good ventilation and comfort. 3、Reflective strips greatly increase visibility and safety at night. 4、Adjustable chest strap and waist strap for snug fit; with a whistle for emergency use. 5、Elastic bungee cord helps store your raincoat, Cycle jersey, etc. 6、D rings for hanging small items. 7、Comes with a 2L water bladder to keep you hydrated all day long. 8、Perfect backpack for Cycle, camping, hiking, traveling, and other outdoor activities. This hydration backpack is lightweight and water-resistant, great for Cycle, camping, hiking, running, and other sports. Features: Durably made with anti-tear polyester fabric, water-resistant and lightweight. Breathable shoulder strap and back for good ventilation and comfort. Reflective strips greatly increase visibility and safety at night. Adjustable chest strap and waist strap for snug fit; with a whistle for emergency use. Elastic bungee cord helps store your raincoat, Cycle jersey, etc. D rings for hanging small items. Comes with a 2L water bladder to keep you hydrated all day long. Perfect backpack for Cycle, camping, hiking, traveling, and other outdoor activities. Specifications: Material: Polyester Color: Black / Blue / Green / Pink (Optional) Dimension: 28 * 8 * 43cm / 11.0 * 3.1 * 16.9in Weight: Approx. 300g / 10.6oz Package List: 1 * Cycle Backpack 1 * Hydration Bladder 1 * Cycle Backpack 1 * Hydration Bladder