Brand: Performance Tool Manufacturer's Part Number: W80530 Part Type: Ignition Testers Product Line: Performance Tool Spark Plug Wire Testers Summit Racing Part Number: WMR-W80530 UPC: 039564805301 LCD Readout: No Checks and Tests Ignition: No Checks and Tests Coil: No Checks and Tests Rev Limits: No Checks and Tests RPM Switch Operation: No Checks and Tests Shift Level RPM: No Checks and Tests Tachometer Accuracy: No Quantity: Sold individually. Performance Tool Spark Plug Wire Testers Performance Tool spark plug wire testers are designed to easily identify damaged spark plug wires. The tester unit flashes in sync with the spark plug firing until it runs across a break in a faulty wire， so you can locate the bad wire and fix it. They're handy to have on hand and are super-easy to use!