S3 Protec Backpack plus hydration. Made for riders, perfect to hydrate and take tools and needed accessories. Comes with the ONE CLIC! front locking system which makes this backpack very easy to to put on and remove quickly. Vented mesh on back side to keep your back well ventilated. Made of waterproof nylon this backpack is very light and comfortable with a carrying capacity of 15 Liters (approx. 4 gallons) and comes with a 2 Liter (approx. 1/2 gallon) hydration bag. There is an elastic spider on the outside for your rain jacket along with safety reflective strips.