Kiwi Climber wrote a review of Black Diamond Winter Bivy Sack on October 10, 2008
I agree with other reviewers. This thing doesn't breathe. The inside was wet from condensation after 1 night in a snow cave. Talked to an R&D guy for Kiwi company Macpac who tested Epic fabric way before BD used it. The verdict was "not the most breathable fabric around..or the most waterproof ... Ok for N America dry snow but not kiwi wet snow."