The Spark helps you sleep well, even when the mercury falls to 15 degrees. With Partial Flex construction youll sleep more comfortably and more warmly than ever before. All without adding noticeable weight We generously fill the continuous baffle construction with 800-fill down, distributing more through the torso to bolster warmth. The down-filled draft tube and Jacket Hood take a miserly approach to your bodys warmth-they horde it greedily Twenty-denier shell material wont sprout down, resists tears, and saves on weight, too. The Spark stuffs to a tiny seven-by-17-inch package.