2 47 SYLVANIA Engraved Base Globe HiFi Radio Amp Vacuum Tubes Codes F3 Strong
2 47 SYLVANIA Engraved Base Globe HiFi Antique Radio Amplifier Vacuum Tubes Matching Codes F3 Strong. Tubes Test New, Strong & Balanced 90 and 90. Beautiful Pair of tubes. Tubes Tested on a TV-7D/U Tester.