This is the rotor for the FAIRBANKS-MORSE FMX4B16A-1 magneto on most SA-200 or SA250 Lincoln Pipeliner portable welders. Also Fits: Fairbanks Morse Magnetos: FM-J4, FM-J4A, FM-J4B3, FM-J4B, FM-JV4, FM-4B, FM-X4B3, FM-4B16A, FM-ZV4; all with 2 piece cap and clockwise ro...