The Moog Prodigy was a monophonic analogue synthesizer produced by Moog Music from 1979 to 1984. Of the 11,000 produced, versions released after 1981 included a control voltage/gate input on the back that allowed the VCF to be triggered and controlled by an external source. These later versions began at serial number 4610. The official model number of the instrument is 336. 336A would indicate a domestic (US) model, while a 336BX would indicate an export unit.