(!!!!) 6973 RCA gray plate NOS 1970's (48.5ma)
(!!!!) 6973 RCA gray plate NOS 1975 (43ma)
(!!!) (Best Pair) 6973 RCA NOS same build 1960-1970 (40ma and 40ma)
6973 RCA black plate branded GE used/strong 1950's (45.8ma)
6973 RCA black plate used/good 1950's (34ma)
6973 RCA branded Raytheon black plate NOS 1960 era (51ma)
6973 Sylvania gray plate NOS 1970's (61ma)