Made with a 20-denier nylon ripstop fabric the Therm-a-Rest Stuff-It™ Pillow doubles as a sleeping bag stuff sack while you're on the trail. Stuff some clothes into the bag at night and you're ready to sleep--and in the morning the DWR finish eliminates any concerns about waking to drool all over your fleece. Choose the size you need based on the stuffed proportions of your sleeping bag or bivy sack.