This is an O.S. #7 Glow Plug. Recently developed to focus on easier running at low and medium speeds, this plug is a slightly hotter heat range than the O.S. #8 plug. This plug is ideal for helicopter engines with superior performance around hovering RPM range, which is critical for smooth and powerful 3D and F3C type flight. Also great all around plug for most 2-stroke standard plug airplane, helicopter and car engines.
| Model | Heat Range | Description |
| No.6 | Hot | Formerly known as the OS A3 plug. This hot plug will provide a more stable idle and crisp acceleration when compared to a cold plug. This plug is recommended for low nitro content fuels and .12 class engines. |
| No.7 | Medium Hot | Slightly "hotter" than the #8 and ideal for the constant "on/off" throttle action in 1/10 and 1/8 scale racing. |
| No.8 | Medium | A medium heat range plug for 1/8 scale racing and most .12-21 car, boat and truck engines. |
| No.10 | Cold | Formerly known as the OS A5 plug. This is now rated as a cold plug and is recommended for high nitro content fuel. This cold plug will produce the most power, but will provide a less stable idle and a narrow tuning window |