DESCRIPTION

Convert your 3-season sleeping bag to a winter/expedition bag with the Down Upgrade layered inside--adds 25 degrees F of warmth to your bag. Zips into most mummy bags; webbing tie-outs attach to loops in another Mountain Hardwear sleeping bag for stabilization. Can also be used alone as a summer bag, rated at 40 degrees F. Upgrade Hood (sold separately) converts Down Upgrade into a full-featured, hooded, lightweight sleeping bag. Double draft tubes seal in heat along zipper.