These T-shirts are manufactured with Textiles from proprietary and inherently nonflammable fibers produced by Chapman Thermal Products. CarbonX Textile T-shirts are heat and flame resistant and wick moisture off your body with very minimal moisture retention in the fabric itself. It is recommended that you professionally dry clean or home launder these T-shirts before initial use. You should always replace these T-shirts if they have been exposed to extreme heat, flame, or any type of volatile chemicals. XXL are an extra $15.