(!!!!!) (Recommended Single) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's (53/40 and 53/40)
(!!!!!) (Recommended Single) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's (56/40 and 60/40)
(!!!!) (Best Pair) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's 1% matched (54-54/40 and 54-55/40 x 2 tubes)
(!!!!) (Best PAIR) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's 1-2% matched (53-55/40 and 53-55/40 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 (48/40 and 49/40)
(!!!!) (Recommended Pair) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's 1% matched (52-55/40 and 53-55/40 x 2 tubes)
(!!!!) (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 (54-54/40 and 54-55/40 x 2 tubes)
(!!!) (BEST PRICE) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's (3 in stock)
(!!!) (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 (54/40 and 54/40)
(!!!) (Best Value) JAN-6X4WA Sylvania NOS 1972-1979 (2 in stock)
(!!!) (Recommended 6X4W) JTL-6X4W Tungsol NOS 1955 curved "D" getter halo (57/40 and 60/40) slightly tilted glass
(!!!) (Recommended RCA Pair) 6X4 RCA NOS 1960's (51-52/40 and 51-53/40 x 2 tubes)
(!!!) (Recommended Single from 1955) JTL-6X4W Tungsol NOS 1955 curved "D" getter halo (2 in stock) (best sound)
(!!!) (Recommended Single) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's (53/40 and 54/40)
(!!!) (Recommended Single) 6X4 SER = LM Ericsson Sweden "D" getter NOS 1950's (54/40 and 55/40)
(!!!) (Recommended Single) JTL-6X4W Tungsol NOS 1955 curved "D" getter (50/40 and 52/40)
(!!!) 6X4 Tungsol "U" getter NOS 1950's redated in 1977 (56/40 and 63/40)
