These MSD digital shift lights can be installed on everything from 1-cylinder points-triggered engines to Modular Ford engines with coil-on-plug technology. The tiny digital controller inside of the compact housing gives you the ability to program the rpm activation points through the easy-to-view LED panel and two programming buttons. When the engine reaches the activation rpm the six red LEDs illuminate brightly enough to alert your senses to throw the shifter at the exact rpm. You can even program up to four different rpm values for different gears! MSD digital shift lights can be installed on up to 12-cylinder engines on stock ignitions or high-powered aftermarket systems.