5Z4 CBS NOS 1954 (53/40 and 55/40)
5Z4 GE Coronado NOS 1950 (48/40 and 50/40)
5Z4 GE NOS 1950 (54/40 and 56/40)
5Z4 Ken Rad NOS 1946 (53/40 and 53/40)
5Z4 Ken Rad NOS 1949 (53/40 and 53/40)
5Z4 RCA JAN NOS 1959 (51/40 and 51/40)
5Z4 RCA NOS mid-1940's (50/40 and 51/40)
5Z4 Rogers Canada NOS 1959 (51/40 and 51/40)
5Z4P Chinese (Best sub is 5Z4G or GZ30)
6004 CBS Hytron NOS (sold out)
6106 Bendix used/good 1950's small hairline crack in base (50/40 and 53/40)
6AL5 GE NOS (48/40 and 48/40)
6AL5 RCA NOS (2 in stock)
6AL5 Sylvania Canada NOS (48/40 and 49/40)
6AL5 Sylvania NOS (3 in stock)
6AL5 Tungsol rebranded GE NOS 1966 (48/40 and 50/40)
6AL5 US Brands used/good (50 in stock)
6BW4 Sylvania black plates used/good 1954-1955
6CA4 RCA branded Super Airline NOS 1960 era (54/40 and 54/40)
6CA4=EZ81 RCA used/good 1962 (53/40 and 53/40)