Specification: ?SAE: .02 to .100 ?Metric: 0.6 to 2.4 mm ?Material: zinc alloy ?Size: diameter of about 1.5 inch/ 3.8 cm ?Color: silver Package includes: 10 x Spark plug gap tools Precise scale: The spark plug gap gauge ranges from 0.020 to 0.100 inch, with a simple and easy-to-read scale, you will be able to use this gauge tool to measure accurate crimping. Easy to carry: There is a small hole on the spark plug gap gauge, you can string them on the keychain for you to use it at any time. This spark plug gap gauge is perfect for DIY automobile maintain use or the professional mechanic.Spark plug gap gauge tool measurement coin-type 0.6-2.4mm with flanged hole to adjust the side wire without damaging the center element and outer rim to measure the electrode gap. Note: Due to manual measurement, please allow slight differences on size.