Old AC only Thunderbolt.  Works great, paid $35 for it at a garage sale.  Soon to be replaced by an old MW AC/DC machine.  I had one before and it was a great machine.  I bought this one at the Auction for $30 and it included a high frequency unit with TIG torch, cables, hose, and regulator.  Not really into TIG so will probably sell cheap or give away with another 220A AC machine I have up for sale.  I also have a Miller 250A Dial Arc I need to check out but need to install a 50A outlet.  Probably sell it if it works OK, takes up too much space in my small shop and exceeds my needs.  Bought it cheap.  Yea I dabble in this stuff some, have several O/A sets laying around.
Ron