REI Stuff Sack Pillow
Here's what other sites are saying:
Doing double duty, this REI 25L stuff sack becomes your pillow once you make camp. Lined with soft fleece-turn the stuff sack inside out, stuff with clothing, and you have a cozy pillow! Made from water-resistant, coated nylon with drawcord/toggle top closure. Handle sewn on bottom of sack makes removing your stuffed sleeping bag easy.