The Dry Sack is a compression stuff sack that features Air Control. Air control is a waterproof air permeable fabric, which allows you to compress the air out and doesn't let water in. This high-tech fabric gives you the ability to compress the contents while maintaining its waterproof integrity fully. The Dry Sack is the perfect compression stuff sack for wet environments (not submersible). 7164011 Blue/Gray 10L 7264011 Blue/Gray 20L 7364011 Blue/Gray 35L 7464011 Blue/Gray 45L