Control voltage on Harley-Davidson 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. A lower-voltage style is available to lower the heat level in the battery where battery is enclosed in center of oil tank. Made in the U.S.A..