This is the Novarossi "Ultra" #7 cold standard glow plug. This is a great plug for high nitro content .21 race motors. It is usually too cold for 1/10th scale motors.
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.
The Novarossi line of standard glow plugs are available in the following variations:
- #4 - Very hot filament glow plug
- #5 - Hot glow filament plug
- #6 - Medium filament glow plug
- #7 - Cold filament glow plug
- #8 - Very cold filament glow plug