You are bidding on a new old stock RCA Radiotron type 808 radio tube with original box and packing, from 1945. I do not know how to test it, but the filament lights, and I get some emission from it. It is a new old stock tube, so I will guarantee it to be a good useable tube. It is a 50 watt 7.5 volt filament transmitting tube, but I understand that now these are used for audio amplification. It should sound great! Shipping weight is 1.5 pounds by priority mail in the US. Please see my other auctions for more interesting tubes and radio items.