You are bidding on a B&K Model 707 Dyna-Jet Dynamic Mutual Conductance TubeTester. I believe it is ingood working condition. I tested a variety of tubes, and it gave accurate readings on both the upper and lower testing phases. Included is the tube testing chart and original operating manual. It is in nice clean condition inside, but there is slight rust on the metal latches, and some scuff in the oil cloth case. It uses multiple sockets, and many have... the tube type marked by the socket for ease in testing. It tests octal tubes and newer, as there are no sockets for the earlier fat pin tubes. It was designed for use by a TV technician, but also tests the later audio tubes. It measures 16 1/4 by 16 by 6 inches is size, not counting the handle or feet. This is a nice clean, high quality tester, that should be put to use. Shipping weight is 19 pounds. Please see my other auctions for more radioand audio items and tubes.