Nathan firestorm hydration backpack the nathan firestorm hydration backpack is a versatile backpack that is great for both running and cycling featuring a spacious main compartment along with smaller pockets to the front sides and straps that is perfect for keeping nutrition and bike tools close at hand this nathan backpack also features a 2 litre hydration bladder that fits snuggly into a sleeve at the back of the main compartment teamed with holding lops to the edge of the zips to hold th