Feature:1. Universal Tool: The tool is universal for 10mm 12mm 14mm 16mm spark plugs, as well as compatible with 6061, 5671A, BKR9EIX and similar spark plugs.2. Powerful Function: The tool could provide you with perfect every time, just place your onto the tool, extremely easy and convenient to use.3. Match to Use: The heavy duty caliper come with a feeler gauge, you can use with both to get your desired thickness, bring you more convenience.4. Spring Back Phenomenon: It is pretty common for some spark plugs electrode to spring back, if your target is 0.44mm, we suggest to use 0.42mm, then you can get it to 0.44mm when it spring back.5. Recommendation: If the metal tool gets wet, you can use compressed air to dry and apply lubricant (not included), to get high performance again.How to Use:1. Simply place your spark plug into the gap tool.2. Use your desired size feeler gauge for gap thickness.3. Turn the knob with the feeler gauge in place till the side electrode compresses to the desired gap thickness.Specification:Item Type: ToolMaterial: MetalApplication: Universal for 10mm 12mm 14mm 16mm Spark Plugs.Compatible with 6061, 5671A, BKR9EIX and similar spark plugs.Not compatible with 18mm thread and longer style spark plugs! Package List:1 xSpark Plug Tool1 x Feeler Gauge