The XL cover is not big enough for an Aether 70 with a Thermarest Z-Lite SOL (accordion style) sleeping pad mounted horizontally to the back. I tried mounting it vertically, and could barely get one of the pack's back straps around the pad even though the pack is far from stuffed and has only 30 pounds in it. The cover barely got around the pack. Pretty frustrating, especially since the Aether Owners Manual shows the pack with this style sleeping pad attached to it.
San Diego, CA