Insul-Fleece is an insulating material ideal for pot holders, oven mitts, and casserole covers. It can also be used for lunch sacks as it works with cold as well as with hot. The material is breathable and won't break down with washing. The polyester fibers resist conduction while the mylar resists radiant energy. Machine wash warm. Tumble dry. 100% Polyester & Metalized Mylar.