THIS UNIT IS A PIGGYBACK ITEM AND PLUGS INLINE TO THE ECU. ALLOW CONTROL OF FUEL MIXTURE, IDLE AND THROTTLE RESPONSE. THESE UNITS WERE VERY EXPENSE WHEN NEW, AND A GOOD OPTION IF NOT WANTING TO UPGRADE ENTIRE ECU. HAS EVERYTHING NEEDED TO RUN IT. MAIN CONTROL UNIT, HARNESS, AIR TEMP SENDER AND MANIFOLD PRESSURE SENSOR. gOOD THING ABOUT THIS. U NEED NO AIRFLOW METER. LOOKING AROUND 300ONO FOR QUICK SALE