(!!!!) (Best Pair) 5R4GB GE black base NOS 1981 (50-52/40 and 50-53/40 x 2 tubes)
(!!!!) (Best Pair) 5R4GB GE black base NOS 1981 (51-53/40 and 51-54/40 x 2 tubes)
(!!!!) (Best Pair) 5R4GB GE black base NOS 1981 (51-54/40 and 52-55/40 x 2 tubes)
(!!!!) (BEST PAIR) 5R4GYB RCA and RCA branded Westinghouse NOS 1961-1970 (50-52/40 and 50-53/40)
(!!) (SINGLE) 5R4GYB RCA NOS 1963 large getter (48/40 and 50/40)
(!!) 5R4GB GE NOS 1983 (54/40 and 56/40)
(!!) 5R4GYB RCA like new 1963 a few oxide filament flakes inside tube slightly tilted glass (50/40 and 52/40)
(!!) 5R4GYB RCA rebranded Raytheon NOS 1960's (50/40 and 53/40)
(!!) 5R4GYB RCA used/very good 1961 (48/40 and 51/40)
5R4GYB RCA brown base like new 1970's part of glass partially melted into bottom mica (48/40 and 49/40)
5R4GYB RCA brown base NOS 1970's part of glass melted into bottom mica (50/40 and 53/40)
5R4GYB RCA used/strong 1970 (52/40 and 54/40)
5R4GYB RCA used/very good 1964 (51/40 and 54/40)
5R4GYB Sylvania NOS 1970's (52/40 and 49/40)
