(!!!!) (Recommended PAIR) 5U4GB Raytheon NOS "O" getters 1962 (58-60/40 x 2 tubes)
(!!!!) (Recommended Pair) 5U4GB RCA NOS and like new 1962 (56-58/40 and 56-58/40)
(!!!!) (Recommended Pair) 5V4G National Union NOS 1951 same date codes (58-59/40 and 57-58/40 x 2 tubes) 1-3% matched
(!!!!) (Recommended Pair) 5V4G RCA 1950's low hours/like new (60-62/40 and 60-64/40)
(!!!!) (Recommended Pair) 5V4G RCA NOS 1948-1950 some stains on glass (57-58/40 and 58-58/40)
(!!!!) (Recommended Pair) 6106 Bendix 1950's rebranded 5Y3WGTA Heintz & Kaufman NOS (64-66/40 x 2 tubes)
(!!!!) (Recommended Pair) 6106 Bendix NOS 1950's rebranded 5Y3WGTA Heintz & Kaufman partially faded printing (66-69/40 x 2 tubes)
(!!!!) (Recommended Pair) 6CA4 GE NOS slightly tilted glass 1% matched (54-54/40 and 54-55/40)
(!!!!) (Recommended Pair) 6CA4 RFT East Germany (Funkwerk) NOS 1970's (48-49/40 and 48-49/40)
(!!!!) (Recommended Pair) 6CA4 RFT East Germany (Funkwerk) NOS 1970's (47-48/40 and 48-48/40)
(!!!!) (Recommended Pair) 6CA4 RFT East Germany (Funkwerk) NOS 1970's (49-49/40 and 48-49/40)
(!!!!) (Recommended Pair) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's 1% matched (53-54/40 x 2 tubes)
(!!!!) (Recommended Pair) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's 1-2% matched (52-54/40 and 51-53/40 x 2 tubes)
(!!!!) (Recommended Pair) 83 GE NOS 1960's (62-65/40 and 62-63/40)
(!!!!) (Recommended Single) CV378=GZ37 Mullard UK NOS 1967 (52/40 and 54/40) 1-3% section balance
(!!!!) (Recommended Single) GZ37 Mullard UK NOS 1966 (50/40 and 51/40)
(!!!!) 5AS4A Raytheon "D" getter 1960 era (58/40 and 62/40) (uprated 5U4GB)
(!!!!) UX-280 RCA Radiotron Balloon used/60% 1930 era some white oxide flakes inside tube (38/40 and 38/40)
(!!!) (Best Matched Quad) 5Y3GT Philips Holland NOS 1960's (1 set of 4)
(!!!) (Best Mullard Pair) EZ80=6V4 Mullard La Radiotechnique Chartres plant France NOS "O" getter halo 1970 (64-64/40 x 2 tubes) 1% matched