Currently there are 2 heads available for the beseler 45. The good old 45s which is just bulb and filter. I believe Nick has this one. The Universal 45 has 3 bulbs and requires a controller to go with it. You can get either a VC or a color controller. I am not familiar with this head.
I have what is called "color computer head" which very much the same as the 45s but the filter values are measured by the sensors in the mixing chamber and displayed in digital form with LED. I like this one very much, as the filter values will change with bulb aging and very consistent.
There was also the Minolta/Beseler 45A, which used repeating strobes with 4 flash bulbs. I heard that this one is very troublesome.