|Sure-Gap is designed for use on all massive electrode aircraft spark plugs. Saves time and money, eliminates guessing of plug gap, prolongs plug life and ensures peak performance. 18mm. 1lbs shipping weight.|
Simple device seems best for making controlled gap changes in the spark plug. With spark end of the plug inserted the thumb screws and be turned making fine , gap-narrowing adjustments. Well made, simple, reliable.
Its cheap, it works. Enough said.
Exactly as expected. Not fancy, but does the intended job very well.