BEWARE of units showing rust--it really ate those chassis quickly, and rust is usually a sign of abuse or neglect. Such amps almost always need new filter capacitors, and often new power tubes. Once rebuilt they are as good as new amplifiers in performance. Ebay can be a dangerous place to look for old tube amps, so be aware of this. If you win a bid, tell the owner that you won't accept an amp that has a bad transformer, lots of rust, or other major problems. If they act squirrely, CANCEL the bid.