One new Brembi brand ignition rotor, part number 9605, 4B.  This fits:

Fiat 500C 2nd Series 1953 - 1954

Fiat 500 2 cylinder with 180 watt or 230 watt generator 1958 - 1960

Fiat 600 with 180 watt generator 1955 - 1958

Moretti 750cc 1957 - 1960