Pot holders, oven mitts, and casserole covers are made functional and safe with Insul-Bright! Consists of hollow, polyester fibers needle punched through a nonwoven substrate and through a reflective metalized poly film. The hollow fibers resist conduction while the reflective metalized poly film resists radiant energy resulting in the energy, hot or cold, being reflected back to its source. No Pre-wash Necessary. Machine Wash and Dry. **At least one layer of cotton batting is recommended with Insul-Bright when used in oven mitts or pot holders. Insul-Bright is heat-resistant, NOT heat-proof.