It's a specialized glow plug. Some of the Turbo plugs for RC car engines cost as much or more.
Hey Bax,
My point wasn't referring to the cost of the glow plug. I was refering to the the fact that they take the ignition off this engine and add a $12 glow plug and charge more for the package. Certainly the ignition components cost more then a glow plug.
Just saying...
Smooth FLying....