1960 CBS JAN 12AU7 black plate triode tube date code 6016

Tested at 2200/2200 uM micromhos on a restored/calibrated Hickok 539B tube tester, whereas 1950 uM micromhos is the minimum acceptable value.  

Please note test values may differ slightly from tester to tester and not responsible if your tester reads it differently,

Values are added as a means to show the tubes indeed tests strong/new, not an exact science. Your results can/may vary.