The Ultimate! - Increase Glove Resistance to 1,000° F (to 538° C)- Rated to 1,000° F (See Heat Resistance Note Below)- Pair of Tempflex Shields For Gloves - Slip Over - Tempflex is Gold Kevlar™ (only by Dupont) Heat ResistanceIs not an exact science...The ability to resist heat is a variable. In addition to the quality of the material used, heat resistance is also dependent upon the length of contact time, the pressure you apply when holding the item and the weight of the item.