This is one Novarossi #5 long body "Ultra" Turbo glow plug. This is a hot glow plug intended for use in .21 race engines with high nitro content fuels. This plug works great in the new O.S. VZB V-Spec race engine which needs a hot Turbo plug. It is also the plug of choice for the Novarossi 421B race engine.
The "Ultra" line of plugs from Novarossi are different from regular plugs in that the hole where the filament is located is slightly larger in diameter, and the glow plug element has a special coating. The new coating is intended to make the plug be more durable, while the larger diameter hole is designed to improve the idle and throttle response of the engine.
