(!!!) (Best Value Pair) 7868 RCA NOS 1965-1970 era (47ma and 50ma)
(Single) 7868 Sylvania branded Philips NOS 1970 era (47ma)
7591 Fisher Westinghouse used/good/75% 1963 (43.5ma, Gm=7450)
7591 Tungsol used good 1963 (55ma, Gm=8100)
7591 Westinghouse branded RCA NOS 1963 (51.5ma, Gm=9050)
7591A Sylvania branded RCA coin-base NOS 1970's (63ma, Gm=10,000)
7591A Sylvania branded RCA used/75% 1968 (51ma, Gm=7,600)
7868 GE branded RCA NOS 1970's (62ma)
7868 RCA black plate tipped top NOS 1960 era (59ma)
7868 Sylvania NOS 1976 (71ma)
7868 Sylvania tipped top used/good 1970 era (48ma)
7868 Wurlitzer RCA black plate tipped top NOS 1962 (48.5ma)