Deluxe noid lite set includes lights to check TBI systems on GM, Ford and Geo; GM and Bosch PFI; GM SCPI. Noid lites are the fastest and easiest way to check electronic fuel injection signals. By simply plugging the noid lite into the injector wiring harness and cranking the engine a flashing light will indicate normal pulsing voltage. Set comes with a molded plastic carrying case. Ten piece set includes: '82 and newer GM square 4-pin connector and '87 and newer flat 4-pin connector. Noid-lites also available separately.