Our ESR127 is a high quality and better-than-OEM regulator/rectifier for your Honda TRX300EX. We built this ESR127 using the latest technology in regulator circuitry, and use a very efficient heat sink to get rid of the heat quickly and efficiently. ESR127 controls the output voltage very accurately resulting in a perfect rate of charge for your ATV's battery across the RPM range. Just as with all other regulator/rectifiers manufactured by ElectroSport our ESR127 comes with a full one year warranty.