Drag Specialties Solid State Regulator For Harley Replacement Rotor for Drag Specialties High-Output 54A Charging System. Features: High-reliability 12V regulator Features rugged aluminum alloy construction Provides accurately regulated voltage under all electrical loads, have no relay contacts to wear or become maladjusted Environmentally sealed for protection against moisture and shock Direct OEM replacement for Drag Specialties High-Output 54A Charging System 550-2557 (sold separately)