Whether you are building a custom engine or cleaning up your engine bay with the PPE Silicone Coated Fiberglass Heat Sleeves. These sleeves will protect all your sensitive hoses, wires, and cables from heat damage. The silicone-coated, woven fiberglass material, these sleeves are capable of withstanding 500 degrees on a consistent basis with short excursions to 2200 degrees. Heat Sleeves should be used anywhere sensitive items, such as vacuum/boost lines, fuel lines, electrical wiring, or coolant hoses come in contact with (or are in close vicinity to) hot engine parts, such as intercooler tubing, exhaust pipes, turbo housings or certain electrical modules.