Features Stow-on-the-Go(TM) trekking pole attachment External hydration sleeve in backpanel simplifies refilling and protects pack contents from spills New IsoForm CM(TM) hipbelt balances firmness and cushioning for optimal carry LightWire(TM) peripheral frame effectively transfers load to hipbelt Front J-zip provides quick access to main compartment Description Product Description The bestselling backpacking series on the market just got even better. Known for its ability to be taken all over the world, from the summit of Everest to a backpack trip through your local wilderness, the fourth generation of Aether/Ariel builds upon its reputation for combining clean design, custom fit and outstanding load carrying comfort. Amongst a plethora of upgrades, the new IsoForm⁴ CM™ hipbelt adds stiffness and padding for even better performance with heavy loads. Amazingly, all this comes with no increase in weight