(!!!) (Recommended Pair) 6C8G National Union round black plates 1950 era used/very good (3.4/2.8ma and 3.3/3.4ma) (very close Gm)
6C8G CBS NOS 1950's (like RCA) (3.7/4.1ma)
6C8G Ken Rad like new 1940's (3.8/3.1ma)
6C8G National Union NOS 1950 era (3.6/5.8ma)
