Excellent duvet, after much research we concluded that wool is the material. It provides a lot of warmth without the excess that down has and without sweating. Its use is with a duvet cover. The carrying bag is also well-made, in king size dimensions, it can be used as a pouf if you put foam pillow inside. The only negative thing about duvets with percale cotton fabric is the noise they make when you change sides, but they have a very good feel. I would definitely recommend it, we ended up choosing it because its dimensions match the majority of duvet covers on the market in king size, unlike some very impressive and popular models that have their own dimensions, limiting options.