Insul-fleece is a needle-punched, polyester fleece, which can be used as an insulation material for home decorating, sewing and craft projects. It reflects heat or cold back to the source. This is the perfect inner lining for lunch bags, table runners, placemats, pot holders and oven mitts. We recommend that an additional layer of cotton batting be used in pot holders or oven mitts. Insul-fleece is heat resistant, not heat proof. Do not use in microwave.