NOS MESA BOOGIE EL34 STR447 Red AC 10 Matched Power Tube Pair Hickok Maxi Test ¥
They test NOS but show signs of being installed in amp. Box shows signs of wear. Mutual Conductance Test: 6100 & 6200 / 6000 (NOS MINIMUM). Test results will vary between testers as it is not an exact science.