ESR916 is a high quality regulator/rectifier that replaces the OEM part on various Aprilia and Vespa models. It has been developed with the newest power circuits inside and thanks to its better heat sink capacity it is far superior to the OEM regulator it replaces. Output voltage is controlled accurately by the internal regulation circuits and you will see a stable output power across the RPM range. Like all regulator/rectifiers manufactured by ElectroSport this ESR916 also comes with a full one year warranty.