This is a 5L professional cycling backpack with 2L water bladder,capable for storing most necessaries for outdoor activities,suitable for riding, running and mountaineering etc. Features WATER SUPPLEMENT--Environmental TPU hydration bladder equipped, pressure-tolerant and leak-proof. Drinking the water by the tubedirectly without taking your running vest off or stopping your steps. SAFETY--Designed with reflective strips on the back and the front that is conspicuous in the dark straps to keep you safe. BREATHABLE--Excellent air ventilation system consist of porous mesh back and comfortable cellular cushionprevents stuffiness andreleases pressure to your back. LIGHTWEIGHT--Ultralight backpack with wide,adjustable and breathable shoulder straps distribute weight effectively, reducesstrength consumption. The backpack with 2L water bladder provides you the max support,min burden and more convenience. LARGE CAPACITY--Spacious compartments with 5L loading capacity is large enough for storing most daily needs such as laptop,tablet, purse, books, cellphone, water-bottle and umbrella etc. VERSATILE--Suitable for all kinds of outdoor activities include riding, running, cycling,camping,hiking, mountaineering, outing,or excursions etc. Specification Color: Black/Red/Gray (Optional) Backpack capacity: 5L Water Bladder capacity: 2L Material: Polyester,TPU Package size: 40*27*4cm/15.7*10.6*1.6in Package weight: 360g/12.7oz Package List 1* Backpack 1* Water Bladder