RPM Signal Adapter When adding aftermarket accessories to your Volkswagen or Audi it is nearly impossible to to get an accurate RPM signal. This RPM signal adapter wires into your coil on plug ignition system and provides a traditional tachometer output to wire into accessories. Features Provides RPM tach output For use with with coil on plug ignition systems Perfect for shift lights, nitrous, or injector controllers Applications Universal What’s In The Box 1 Signal Adapter Warranty Auto Meter Limited Warranty