The Marmot Alpinist Bivy is a bivouac sack for the twenty-first century. It is 100% seam taped for waterproofness and durability, weighs in at under a pound, and compresses like magic into any pack. High-tech Marmot MemBrain® fabric breathes easily while blocking wind and water. The Marmot Alpinist Bivy offers awesome minimalist protection for climbers and backcountry adventurers who must travel light. The Marmot Alpinist Bivy provides extreme shelter in a small, compact package.