(!!!) (Best Pair) 6GM5 Sylvania 1960's - 1970 (72ma and 74ma)
(!!) (Best Pair) 6GM5 Sylvania NOS 1970 era same date codes (61.6ma and 62.2ma)
(!) (Recommended Pair) 6GM5 Sylvania NOS 1960's - 1 tube branded Tungsol (55ma and 56ma)
(!) (Recommended Pair) 6GM5 Sylvania rebranded Tungsol NOS 1960's (60ma and 64ma)
6GM5 Sylvania branded RCA NOS (52ma)
6GM5 Sylvania branded Westinghouse NOS 1974 (48ma)
6GM5 Sylvania NOS no printing in RCA box (52ma)
