Made to mimic down insulation, the Marmot Echo Featherless Jacket features synthetic fill that's light and packable but doesn't lose its loft when it gets wet. As much as we like down jackets, they don't handle moisture well, so rain, snow, and sweat can rob them of their insulating power. With the Echo Featherless jacket, we don't have to worry about a surprise shower or snow squall ruining our hike-or our jacket-because its Thinsulate insulation still will keep us warm when wet and will dry quickly to keep us safe in wintry weather. We like this synthetic alternative to down when we're out in cold and damp conditions or layering for high-output winter sports that likely will have us sweating at some point.