This a OE Lucas Relay Jaguar 4.2 E-Type 65-71 Cooling fan, field isolation, ignition, Jaguar E-Type V12 1971 to 1974 AC fan override, XJ6 1969 to 1973 Air conditioning, override , XJ6/12 74-76 Air conditioning, MGB Fan 77-80, MGB Battery cut-off 76-80.