(!!!!) (BEST PAIR) 6C4WA GE JAN NOS 1974-1975 (10.4/10.8ma) (same Gm)
(!!!!) (Pair) JAN-6C4WA Sylvania NOS 1975 (7.8ma and 8.6ma)
(!!!) (Best Mullard Single) 6688=E180F Mullard branded Philips SQ gold pins NOS 1971 (11.5ma)
(!!!) (Best Pair) 6C4WA GE JAN NOS 1971-1973 (9.2/9.4ma) 1-3% matched (Conrad Johnson)
(!!!) (Best Single) JAN-6C4WA GE NOS 1967-1968 (11.8ma)
(!!!) (Best Value Pair) 6C4WA GE JAN NOS 1966-1967 (7.8/7.8ma) 1-2% matched
(!!!) (PAIR) 6C4 GE ribbed plates NOS 1964-1968 (8.8ma and 9.2ma)
(!!!) (Recommended Pair) 6C4WA GE JAN and JG NOS 1965-1967 (8.4/8.8ma) 1-3% matched
(!!!) (Recommended PAIR) 6C4WA GE JAN NOS 1971-1973 (8.4/8.4ma) 1% matched
(!!!) (Recommended Pair) 6C4WA GE JAN NOS 1971-1973 (8.8/9.0ma) 1-2% matched
(!!!) (Single) 6688=E180F Amperex PQ USA NOS "O" getter 1968 (9ma)
(!!) (Best Value Pair) 6C4 Westinghouse Mexico NOS/75% 1991 (7.8/8.8ma)
(!!) (Recommended SINGLE) 6C4WA GE JAN NOS 1972 (10.6ma)
(!!) (Recommended SINGLE) JAN-6C4WA GE NOS 1967-1968 (9.8ma)
(!!) (Recommended SINGLE) JG-6C4WA GE JAN triple mica NOS 1964-1965 (9.2ma)
6100=6C4WA GE 5 star triple mica NOS 1959-1960 (12.6ma) (Premium 6C4)
6688=E180F National UK black plate NOS probably made by Amperex (9ma)
6688=E180F National UK gray plate NOS probably made by Amperex (16ma)
6C4WA Sylvania NOS 1965 and 1971 (read review)
