Permatex Copper Spray-A-Gasket Hi-Temp Sealant is fast-drying, metallic copper sealant helps dissipate heat, prevents gasket burnout and improves heat transfer. Fills minor surface irregularities. Seals instantly. Fills hot spots and surface imperfections. Temperature range -45 C to 260 C; resists all types of automotive fluids, especially petrol.