Controls voltage on Harley-Davidson and Buell alternators, unlike other rectifiers or regulators that dump to ground and cause maximum stator current and higher temperatures. Cycle Electric rectifying regulators block current to control voltage; this reduces stator current, resulting in low temperature and less drag on the motor, which means more efficient operation. Low voltage style features reduced charging voltage to prevent overcharging the battery. Made in the U.S.A.. Not for models with evaporative emission systems (CA).