(!!!!!) (BEST SINGLE) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's (55/40 and 56/40)
(!!!!!) (BEST SINGLE) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's (57/40 and 58/40)
(!!!!) (Best PAIR) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's 1% matched (56-56/40 and 56-56/40 x 2 tubes)
(!!!!) (Best PAIR) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's 1-2% matched (54-55/40 and 54-55/40 x 2 tubes)
(!!!!) (Best Value Pair) JTL-6X4W Tungsol NOS 1955 curved "D" getter halo (best sound) (recommended for Audio Note, Shindo, LAMM) (50-54/40 and 51-55/40)
(!!!!) (Recommended 6X4W) JTL-6X4W Tungsol NOS 1955 curved "D" getter halo (54/40 and 56/40) slightly tilted glass
(!!!!) (Recommended 6X4W) JTL-6X4W Tungsol NOS 1955 curved "D" getter halo (55/40 and 56/40) slightly tilted glass
(!!!!) (Recommended Pair) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's 1% matched (53-54/40 x 2 tubes)
(!!!) (BEST PRICE) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's (0 in stock)
(!!!) (Best Raytheon 6X4) JRP-6X4W Raytheon NOS "D" getter NOS 1953 some production staining around bottom of tube base (59/40 and 60/40)
(!!!) (Best Single) JTL-6X4 Tungsol "U" getter NOS 1954 (54/40 and 54/40)
(!!!) (BEST VALUE SINGLE) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's slightly tilted glass (52/40 and 54/40)
(!!!) (Best Value) EZ90=6X4 Ultron East Germany 1970 era (2 in stock)
(!!!) (Best Value) JAN-6X4WA Sylvania NOS 1972-1979 (5 in stock)
(!!!) (Best Value) JRP-6X4W Raytheon NOS "D" getter NOS 1952 manufacturing stains around bottom (63/40 and 67/40)
(!!!) (Recommended 6X4W) JTL-6X4W Tungsol NOS 1955 curved "D" getter halo (57/40 and 60/40) slightly tilted glass
(!!!) (Recommended Pair) 6X4 RCA NOS O getter 1960's (50-52/40 and 50-50/40 x 2 tubes)
(!!!) (Recommended Pair) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's 1-2% matched (54/40 and 55/40 x 2 tubes)
(!!!) (Recommended Pair) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's 1-2% matched (54/40 and 56/40 x 2 tubes)
(!!!) (Recommended RCA Pair) 6X4 RCA NOS 1960's (51-52/40 and 51-53/40 x 2 tubes)
