Lord Splitboarder wrote a review of Black Diamond Winter Bivy Sack on May 31, 2007
This item performed terribly for me. I used it on 2 overnight ski tours in the Columbia mountains of BC - both times getting my sleeping bag soaked from condensation. I also used it for an overnight well below the snow line and above freezing temps, and it still filled with condensation. This thing does not breathe at all, regardless of temperature, inside or outside of a tent. It sucks, which is a shame as I am normally a huge fan of Black Diamond gear.