O.S. has now introduced new glow plugs that are more suited to rigors of R/C car racing. FEATURES: Designed for high nitro fuels. (25% +) Increased durability at high RPM. Durability under extreme temperatures. Allows for leaner needle settings for higher power and quicker throttle response. This plug is most suited for 1/8 scale, .21 Nitro-powered on-road racing. INCLUDES: #R5 glow plug with gasket