The Winter Kit gives Nano™ year-around versatility. It includes DAC aluminum poles and a WindShield™ curtain. The aluminum poles weigh more and don't pack as small as the IRR™ airbeams, but we recommend them for mountaineering as care is needed to keep moisture out of the airbeam valves in the extreme cold. The WindShield™ fabric curtain adds an extra layer of protection against wind and bitter temperatures. It weighs only 5.7 ounces, and attaches quickly by Velcro® straps and button snaps.