This bag is a rare beast: It tested warm down to 15 degrees below its temperature rating. Our tester, wearing just a single layer of long johns, slept comfortably on a winter trip in Utah’s Bear River Range: “This bag puffs up like it has an internal compressor, and the 800-fill down with vertical baffles kept me in a constant bubble of warmth,” he says. “The hood surrounded my noggin in a cloud of down, and it cinched down tight without a bunch of extra material in my face.”
Despite all this warmth, the Mountain Light packs up to bread-loaf size. The fit is trim across the chest, but our 5’8”, 165-pound tester thought the increase in thermal efficiency was worth the tradeoff. The DWR-coated, 15-denier Pertex Quantum shell is both light and water-resistant. “I woke up covered in frost after an open bivy in Utah’s Cache National Forest, and no moisture penetrated the shell,” reports one tester.
The full-length zipper offers easy ventilation on warmer nights, and it ran smoothly every time, thanks to an effective snag guard (sometimes a challenging feature with these ultralight shell fabrics). $369; 2 lbs. 2 oz.; 15°F; ems.comVertical baffles featuring Flow Gate technology prevent down shifting to the side as you sleep and eliminating cold spots. Unique baffle construction on hood maximizes warmth and comfort. Women's features include unique silhouette, extra down in toe box and mid-torso.