The Osprey Aether 60 is the entry-level model in the lightweight Aether series of men's mountaineering backpacks. Available in three colors and three sizes, the 2010 Aether 60 introduces several new features. The top pocket can be removed and converted into a lumbar pack, and built-in cord loops allow certain Osprey daypacks to be attached. Other key features include an internal compression strap, removable sleeping pad straps, and hydration system support for reservoirs up to 3 liters. The same features are available in the Aether 65 and 75, which offer greater load capacity, and in the Ariel Series, which is designed for women.