Weight: 0.36The term "indexing" when referring to spark plugs, is the process of adjusting the spark plug electrode to the correct position in the combustion chamber. More complete combustion and consequently more horsepower is developed by indexing the electrode gap toward the center of the piston, favoring the exhaust side if possible.AccelAnodized Indexing ToolFits all models with 14mm spark plugsHelpful when preparing spark plugs for future use, such as at the race track or to carry in your tool pouchBy: HOLLEY PERFORMANCE PRODUCTS,INC.