How to choose a MH ballast ?

How to choose a MH ballast ?
The easy part – is to choose the right W
so if the lamp has 150W I need 150W ballast

But what I do not understand:
What about the Volts?
So if the lamp operates in 90V and I find a ballast that operate in 150W
How can I tell if that ballast is good for me?

BTW the lamp is Osram HTI 152 - 90V

What about the electronic ballast can I use different 150W bulbs in them ?
For exmple can I use 230V bulb and 90V bulb in the same electronic ballast ?