You run a single circuit to your shop (say 30-40A 220V with neutral), with one breaker in the main panel, connect it to the panel I am selling, and voila, you are done.
This is a very cheap way to have a lot of protected 20A outlets, compared to alternatives (buying electrical boxes, premium 20A outlets, subpanel, many breakers etc). Nice for a shop where you have a lot of tools that need to be plugged in.
This is a pull from a large 5 kvA working UPS. I have another one, which I will keep for myself.
$25 plus shipping (maybe $10 or so) takes it. Local pickup is free (Chicagoland).