Digital Rpm Window Switch This Switch Can Be Used With An Input Voltage Of 9-18 Volts MSD IgnitionAre you looking for an RPM Switch that will turn a circuit on, then off at a different rpm? How about one for your late model coil per cylinder ignition system? Or, something for your car with dual coil packs? Maybe one for a Viper or even a Harley Davidson? Look no further, our new Digital RPM Window Switch will do it all! This Switch will accept an input rpm signal from a coil negative terminal (for stock ignitions), a tach output from an ignition