The glow plug ignites the fuel in a nitro engine. A glow igniter heats it to start the engine, then the engine’s own heat keeps it firing.

Match it to your engine, fuel and the weather. A hotter plug helps starting and cold running, a colder plug suits high-nitro fuel and hot conditions.

A turbo plug has a tapered seat that seals better and improves combustion in engines designed for it. Use a turbo plug only in a turbo-head engine.

The plug wears with every run, so change it when the engine gets hard to start or idles poorly. Keeping spares is cheap insurance.