The CamelBak Arete 18 50oz Hydration Pack is one of the most versatile packs ever thanks to its lightweight materials and reversible, double-duty design. When you're not wearing it, it reverses into an insulated reservoir sleeve, perfect for holding your water supply steady inside a larger pack. When you just want to take a quick hike, just flip it right side out, and you've got room for snacks, layers, essentials, and 1.5 liters of water. Its lightweight materials and packable design also make it an excellent travel bag that won't add bulk to your luggage. CamelBak has updated this version of the Arete with additional pockets to keep your gear organized, along with a removable sternum strap. When adventure calls, the Arete 18 is there for you!