Your B22 is a 6x6 enlarger.
Just a warning. Gathering missing parts can get expensive, sometimes VERY expensive. I'm going thru that right now with 2 enlargers. The missing parts has doubled the cost of the enlargers. And some parts are just plain HARD to find. So when you get an enlarger, get as much of the parts that go with it as you can. Sometimes it is just a matter of the seller looking into another box for the missing parts.
Get the manual for the enlarger first, then study it, so you know what parts you will need to look for when you pick up the enlarger. And do an inventory of the enlarger and parts. And look for damage. Replacing broken parts will be like missing parts, more $$$ cost.
Look for the parts like the various lens cones for the D-II, negative carriers, and condenser lenses (if separated from the enlarger like on my Durst L1000 and Omega 67).