Universal replacement 6v DC regulator negative ground for bikes using generators. Nice small solid state regulator that can be used on lots of different bikes with 6v DC generators and negative ground charging systems. Comes with good instructions and testing/trouble shooting info. Unit measures 2 1/2" X 1 1/2" in a nice looking finned aluminum housing. NOTE: WILL NOT WORK ON 12V, POSITIVE GROUND OR ALTERNATOR CHARGING SYSTEMS.