Looking at the Arctube support it looks like Venture, also you can use a US CWA or Probe start on a mercury Ballast and 2 wire ignitor, also it's a Fire hazard as the lamp looks like it's covered in sawdust, and the Glass Protector is missing of the fitting, this if the lamp explodes hot fragments (upto 1300 deg C can catch fire to combustable materials below the fitting

I know Venture Lamps are Interchangable for both E39 and E40 Lamp Sockets except for the POMB which have a pin on the side of the cap, and the EX39 which can be used in a standard E39 lampholder bit avoids a Enclosed rated Lamp being used in a Open Fitting which has the EX39 Lampholder.

All the Best

Colin

Sailormoon_01_uk: Regarding to the ballasts, you are right. But in this case, the CWA ballast in this fixture is Israeli, since the original US ballasts desigened for 120V, and therefore can't be operated in Israel.
Eltam Ein-Hashopet also produces CWA ballasts for american lamps, but i think that they have recently cased their productions.
This is a low bay fixture with its glass missing, so if the lamp would be explode, this may cause fire hazard or insulted.
Also, this location in the neighborhood's center is not so clean.
The fixtures are neglected and also, i think there are also many columba livia birds that makes dirty.

Actually...Dor123....in US we have ballasts ranging voltage from 120, 208, 240, 277 and 480....So are you sure this is a 120 volt? Perhaps its a 240 volt?

Also if MH lamps are put in MV fixtures NOT labeled to be MH ballast, I notice they get blackened faster and really blackened too.

Yes the USA have what they call Multitap or Multivolt Ballasts, as Jace mentions, I have a old H30 Ballast kit for operating a 100w US Mercury Lamp on a 120, 208, 240, and 277 volts, see HERE But is Useless as we use 50 Hz Supply and the Ballast is a 60 Hz Ballast, thus it get very hot when operated at 50 Hz supply,

Here in theUK we can get CWA Ballasts for 175, 250 and 400w US Metal Halide Lamps but due to being very expensive they are not so popular users use a simple Choke (Reactor Type Ballast) and a 2 wire ignitor for a 1/4 of the Cost

All the Best

Colin

Colin, not always multiple voltage.....I have a 150 watt HPS ballast that is ONLY 277...no other voltage.... having one volt on a ballast is cheaper than having multiple voltages so sometimes you get multiple voltage, while other ballasts you could buy only one voltage......

Hi Jace

Thats right, some Ballasts are only set at the desired Voltage/Frequency example the USA 120v 60 Hz, while a UK ballast is 240v 50 Hz, others are available as Multi Tap as we seen in the USA from 120 volts to 480 volts and in the UK older Ballasts were made for 200 to 250 volts, I am not sure about the USA but here in the UK some Ballasts can be Dual Wattage for 50/70w HPS, 100/150w HPS and 250/400w HPS, also for Mercury Lamps, they are made in 50/80w, 80/125w and 250/400 watts. there is No Multi watt Ballasts for Metal Halides as we use either HPS or Mercury Ballasts with conjunction with Ignitors, depending on the lamp voltage Current

All the Best

Colin

Jace, how you have magnetic ballasts that can be operated with multiple voltage rating? This is more of a feature of the electronic ballasts.
Our voltage is 230V and the magnetic ballast supplied in Israel, should exactly match the voltage of the mains with a variations for 10%. This is not means that a 220V ballast suitable for operation in Israel, and a 230V ballast is suitable for 240V.
This is different in electronic ballasts that can be found in various voltage ranges.
Perhaps CWA ballast can have features that reactor and choke ballast don't have.

on Magnetic ballast's capable of opperating on many diffrent voltages...my guess is there is more than One Primary Coil.....or there's one coil with Taps on diffrent points of the coil (like an Autoformer) im Not sure....just a theory.