270 gsm - If you're looking for a baselayer to stand up the coldest winter days Mother Nature throws your way - and we've had customers wear Comet on expeditions in Antarctica and Alaska - then you've come to the right place. Duckworth's proprietary Comet fabric is natural-technical mash-up, combining a pure, 100% Montana-grown Merino Wool outer layer and a polyester inner layer. Why the combo? Polyester is hydrophobic, meaning it will wick sweat and moisture right off your skin and into the hydrophilic wool layer; wool chemically begins to get even warmer when introduced to water and water vapor, thus explaining why the Comet Crew will have you feeling dry and toasty even in the nastiest conditions. By the way, Comet is soft to the touch, meaning it works perfectly as a single layer that looks sharp at après ski in the lodge or in the truck between treks. Durable, anti-odor, moisture-wicking, quick-drying, durable, and versatile: your one-stop-shop baselayer.