CustomSeaLife Metal Halide Ballast Question

[sov82]

I have a CustomSeaLife Ballast with 2 175 watt BluelinePlus Metal Halide Bulbs. Does anyone know what type of ANSI Ballast this is?
I have looked all over the ballast and I do not see it anywhere. CustomSeaLife is now out of business so I can't contact them.
Thanks in advance.

 

[golfish]

Probably an M57

 

[sov82]

Is this just an educated guess? I don't want to buy the wrong type of bulb since I'm "forced" to buy online.