Solid state regulator mounts directly to the left end of the generator, eliminating the need for remotely mounted regulator. Includes needle bearing for armature support. Installation instructions are included. Fits Big Twin (panhead / panshovel / shovelhead) 1965 - 1969, Ironhead Sportster 1965-1981 and 45 Servi-Car 1965 - 1973. Not designed to be used with a 5.5 amp battery.