With a 100% nylon outer shell on the outside and nylon lining and polyfill inside, the N-3B stays warm no matter how cold it gets. For further protection and to keep your noggin nice and comfortable, the hood is lined with synthetic mouton fur and trimmed with removable faux coyote fur. If you need to bolt down the hatch for a tighter seal, you can adjust the hood with the take-up strap and drawcord.