The warmest of our down duvet inserts, the Winter Weight is soft and lofty—will keep you toasty even on the coldest nights. This comfy layer is made with pure down encased in a down-proof, 100% organic cotton shell. Stitch-through box construction keeps the fill evenly distributed, so you stay perfectly warm right down to your toes. It’s filled with the same 600-fill-power down as our Three Season duvet, but with added fill to keep you in comfort. The extra filling also means it feels heavier, which helps some people to sleep.