6S4A Raytheon NOS 1961 (20ma)
6S4A RCA branded Sylvania black plate NOS 1960 era (20.6ma)
6S4A RCA USA black plate NOS 1970's (19ma)
6S4A Sylvania NOS 1960's (20ma)
6S4A Sylvania triple mica NOS 1960's (20.2ma)
6S4A Tungsol branded GE NOS 1966 (21.5ma)
6S4A Westinghouse NOS 1963 (23ma)
7N7 Sylvania branded RCA chrome top used/good 1956 (6.6/8.4ma)
7N7 Sylvania chrome top branded GE low hours/tests like new 1957 (7.4/11.4ma)
