Long hiking days are hard on the back, and the Air Support Back Panel on the CamelBak Rim Runner X22 Hydration Pack ventilates the hottest areas. Recycled 210D nylon double ripstop keeps the body strong without adding weight. The pack comes with a Crux 1. 5-liter reservoir that sits in the internal hydration reservoir sleeve. What Our Gearhead(R) Experts Are Saying:"On rough, rocky stretches of trail, the tube trap kept my hydration tube fastened, and the cargo compression held my layers close to my body. With the stability belt cinched, the pack stayed steady through every step."