Originally Posted by Max Power
Beseler includes the negative size in it's names. So the 23 is for 2"x3". The 45s are for 4x5. Omega uses letters. The Omega 4x5s are D types.
Is the Omega a VC? A variable contrast enlarger usually isn't a condensor enlarger.
That's an Omega VC head for the B &C series enlargers. You'll see it's basically a colour head.
Spend some time going over that site. Get the full name on the various enlargers and heads you're looking at.