This is a replacement Aermacchi Electrical Control Unit for OE 74501-73P (shown below). This part has 4 ports and grounds through the body of the unit. The new voltage regulator is slightly smaller than the OE part and requires some minor wiring ( no charge light indicator). ( Instructions included) This part replaces the part shown in the photo(s) below. This Electrical Control Unit should provide an improvement with its more modern circuitry.