The OEMTOOLS 37161 Noid Light Kit includes 8 fuel injector tester lights for some of the most common fuel injector systems on the market, including: GM TBI, GM SCPI, GM PFI, Ford TBI, GEO TBI, Bosch PFI, Bosch Type 2, and GM Multec 2. The noid test lights are easy to use and easy to read. Simply insert them into the wiring harness plug of your fuel injectors one at a time and start your engine. (Note: make sure to unhook your battery to insert the noid light, and then hook it back up and turn on the engine to test the light). Working fuel injectors will cause the noid light to pulse light, whereas failing fuel injectors will create a steady unpulsing light, or no light at all. In this way, you can identify fuel injector issues, and work backwards to the root cause. Injector system issues can be tricky, and our noid light kit makes fixing them much more manageable. Weve designed this tool for professional mechanics, who need to regularly diagnose and fix fuel injector issues in a variety of makes and models. INCLUDES TESTERS FOR THE FOLLOWING INJUECTOR SYSTEMS: - GM TBI - GM SCPI - GM PFI - Ford TBI - GEO TBI - Bosch PFI - Bosch Type 2 - GM Multec 2