Check the listing for details. Precision Feeler Gauge Gap Tool Set for Spark Plugs and More. Condition: New. Listed at 18.39 USD. Feeler Gages are used for adjusting and gauging spark plugs, distributor points and valve clearances, or any other instance of measuring the space between two parts. Our Precision Series Gauges are made of high-grade precision steel with etched numbering for easy identification. Details include: Sizes: .0015 - .035 Inch, 0.04 - 0.88 MM Metric and inch sizes etched on each blade For Auto, Marine and Farm Made of high-grade precision steel. Leaves are etched with size numbers in the thousandths for quick identification. Knurled locknut holds the leaves in desired position. Protective holder protects leaf edges when not in use. Manufacturer look and details may vary