This is a combination of a 16L backpack with a 2L water bladder which are specially designed for bicycle lovers and walkers. Large capacity daypack with hydration insulation layer and helmet bag is spacious enough to store your necessities. Nice bag for running, cycling, hiking, fishing, etc. Nice bag for running, cycling, hiking, fishing, etc. Features: [Backpack] Come with a 16L backpack and a 2L water bladder. Made from tear resistant and waterproof polyester fabric for extreme light weight and durability. 16L large capacity can store basic items needed for daily use. Hydration insulation layer and pipe outlet on the shoulder strap make drinking more convenient. Thicken EVA padded back for maximum breathability and comfort. Outer elastic mesh bag for fixing your helmet, easy to take it to anywhere. Fully adjustable shoulder and waist straps for a custom fit. Zippered waist pockets keep some small necessities handy. Reflective strips enhances visibility and safety. Survival whistle on the chest bag can be used in urgent needs. [Water bladder] Wide opening design, convenient to fill and clean. Soft silicone nozzle with pull-out shutoff valve provides fast water flow. Light weight and slim profile for a quick load into your hiking or camping backpack. Perfect choice for running, cycling, mountaineering, hiking, fishing, cross-country and other outdoor activities. Specifications: Material: Polyester Type: Bag only / Bag + water bladder ( optional ) Bag Color: Black / Red / Orange / Green / Blue / Cyan ( optional ) Bag Capacity: 16 L Bag Size: 45.5 * 18 * 7.5 cm / 17.9 * 7.1 * 3.0 in Bag Weight: 525 g / 1.16 lb Water Bladder Capacity: 2 L Water Bladder Size: 31 * 17.5 cm / 12.2 * 6.9 in Package List: 1 * Backpack 1 * Water Bladder