So the question has been asked many times. What is the difference between the Martin Starflash and the Starflash III?? Here is the difference...
Physical Size: The Starflash III is a bit larger in size. This is due to the plug and switch assembly being a bit larger and in a different position.
Plug: The Starflash III adds a removable IEC style plug as the standard version has a hard wired plug.
Fan. The Starflash III blows air from the rear out of the front of the unit. The standard version pulls air in from the front and blows it out of the back.
Lamp Access: The original version has an access panel on the bottom and the Version III is on the top.
Electronics: The PCB on the version III is better due to some advancements on the auto frequency sensing circuitry.
Labeling: On the original version the specific model (configuration of the dichros on the dish) is screen printed on the front of the unit. On the Starflash III it just states Starflash no matter what model it is. You have to either look at the Martin Serial number sticker (if it is still on the unit and has not come off or is unreadable) or open the unit up to see what unit it is (or simply turn it on).
They both use the same lamp and have a 3 position switch so minimal improvements are on the version III. Both are great units and will almost last forever. The DJ Series is the very first version of the starflash and was only available in multicolor. The Starflash units replaced the Rainbow and Ministar units which used the common 24 volt, 250 watt lamp and were much heavier and bulkier.