It’s durable and stretchy—two qualities that didn’t coexist in the puffy market until now. With the StretchDown Jacket, Mountain Hardwear took stretchy 100-percent polyester fabric, sandwiched its Q.Shield Waterproof Down in the middle, and welded the seams. Result? A superwarm jacket that moves with you and is more durable because there’s no thread in the seams. “I brushed against tree limbs and tossed skis over my shoulder, and didn’t have to worry about losing any feathers,” one guide says. The welded seams also trap more heat than sewn seams, making this toaster best for frigid days (if you’re moving) or just staying warm (if you’re not). “I wore it in camp, chilling at belay points, and on cold resort ski days,” one tester says. Versatility: Since it weighs little and stuffs down to liter-bottle size, we’ll take it backpacking throughout the year. Men's S-XXL, women's XS-XL.