Feathered Friends Vireo
Feathered Friends' Vireo was designed with alpine climbers in mind. It has no zipper, no hood, variable down fill, and weighs only 16 ounces.
Variable down fill means the lower part of the bag has more down fill (rated to 25ºF) and the upper section has less fill (a 45ºF rating). It is designed to be used with Feathered Friends' Volant Jacket (or Icefall Parka or Frontpoint Parka) for full protection. Used without the jacket it becomes a summer bag. This compact, light system is great for climbers, bicyclists or emergency use.