This is a O.S. Engines T-Series RP7 Medium Heat Range Turbo Glow Plug. This glow plug is ideal for .12-.21 size O.S. on road racing engines that create high RPM and require a cold heat range turbo style glow plug.Feature:For: Nitro EngineMaterial: MetalColor: SilverInclude:O.S. ENGINE RP7 Turbo Glow..