Rated for 12F, Fits straight, 135 deg, and 9 deg. boots, Double wall

Spark plug boot heat socks, protect your expensive plug wire set's performance and increase their lifetime. Insul-Boots prevent misfires caused by plug-wire burnout, this helps prevent critical engine damage and loss in performance. This boot heat shield, feature double wall construction provides superior protection. Special heat coatings allow these boot heat shields to reflect and dissipate heat. The universal design fits most boots-even 9 degrees. Insul-Boots are available in six ceramic colors-red, blue, black, tan, yellow and orange and withstand up to 12F. Easy installation: place ring side on end of spark plug boot and slide the wide end towards the wire, ring side of Insul-Boot should rest between cylinder head and top of plug boot.