Glow plug tip; before you thread the plug into a plane, check the setting to get the proper glow. I have recently found a huge difference in the settings needed on the same plug type, even by the same man. !!! It explains why some of my plugs have "burned out" in short order by having too high a setting on my glow driver. I found I can't just set the needle in the "green" any more. That setting is way too high for some plugs and they will burn out in short order!! [>:]