ESR350 is a modern regulator/rectifier that replaces both original (mechanical) regulator and rectifier on the early Yamaha XS650 models. Our ESR350 comes with the correct connectors and was designed to plug into the wiring harness where the original rectifier and regulator used to plug in. ESR350's rectifier bridge is much more efficient than the old OEM rectifier which really helps low rpm output from the system. Output voltage is also much more stable than what is possible with the OEM units. Check to make sure your alternator rotor is still within spec (between 4.5 and 5.2 Ohms). These rotors often fail causing the alternator system to stop charging, our replacement part is ESF650. Like all our parts also our ESR350 comes with a full one year warranty.