Hickok Model 539B Tube Tester. The tester looks very good and shows only moderate wear. I recently acquired it from the estate of a long-time audiophile. The tester comes with original manuals, supplements and other information as shown in the images. I have tested several tubes with it and it works great. It appears to have been recently calibrated and comes with calibration instructions and check sheets. As you can see, the tester calibrates to the line voltage. I have also included an image of a 12AX7 under test. The tester has some nice socket savers installed as can be seen in the images. The tester also comes with the CA-5 adapter and manuals for testing compactrons, large novars and other tubes. The adapter alone sells for $150+. This is a very fine tester and if I did not have so many testers, I would not sell it. Buyer pays $35 shipping in CONUS.