This set includes 30 spark plug index washers made of thin copper. They are 0.012 inches (0.3mm) thick and are ideal for indexing spark plugs, acting as excellent spark plug shims.
These copper spark plug indexing washers are easy to use. First, remove the old washer from the spark plug if there is one. Then, place the new washer on the spark plug. Make sure it's properly seated. When installing the spark plug, tighten it carefully as per your vehicle's manual. Keep these washers in a dry place to prevent rusting. If they get dirty, you can clean them with a mild cleaner. Avoid using sharp tools on them as it might damage the washers.
