84=6Z4 Greylock by National Union like new 1950 era (48/40 and 53/40)
84=6Z4 Philco used 1950's (44/40 and 46/40)
84=6Z4 Raytheon engraved base used/good 1930's (49/40 and 52/40)
84=6Z4 Raytheon engraved base used/tests like new 1930's (58/40 and 60/40)
84=6Z4 RCA NOS GT-shape glass slightly tilted glass 1967 (44/40 and 47/40)
84=6Z4 RCA NOS GT-shape glass tilted glass 1967 (47/40 and 48/40)
84=6Z4 Wizard by Sylvania used/good 1940's (50/40 and 52/40)
