ACCEL Extreme 9000 Ceramic Boot Wires feature ultra high-temperature, double silicone, 8mm, 500 ohms/ft Ferro-Spiral core wire developed for performance use. The wire is rated at 600 degrees Fahrenheit peak and the Ceramic boots withstand up to 2,000 degrees. These race wires also feature Mr. Gasket Inferno Shield Thermal Sleeving to increase the heat resistance of the wire to 1200 degrees Fahrenheit. The Inferno shield is held in place with a high temp heat shrink so you do not have to worry about the shielding moving. Great for running headers with close tolerances, an engine bay with little room or an application with high under-hood temps due to extreme racing conditions. ACCEL Extreme 9000 wires offer excellent energy delivery to the spark plugs through stainless steel spark plug terminals, while providing the highest level of RFI/EMI suppression.