Adjust The North Face Chameleon Hydration Packs size to meet your needs. When you go on a fast, post-workday hike or bike ride, fill the 100-ounce reservoir you can never have too much water, grab an extra layer and a snack, and go. If you plan to hike 16 miles to an alpine lake and back in a day, then the Chameleons width expands two inches to hold lunch, more layers, first aid items, and anything else you need for your adventure. This Flight Series pack even has a lash point for your trekking poles. The breathable mesh on the Chameleons panel and straps ensures you dont form pools of sweat on your back and shoulders, and a removable waist-belt helps secure your load. The North Face partnered with Nalgene to bring you Encapsul reservoirs, which are sturdy, tasteless, antimicrobial, and BPA-free.