(!!!) 6S4A RCA black plate NOS 1960's faded printing (20ma)
(!!) (Best Pair) 6S4A RCA NOS 1970's (34ma and 35ma)
6S4A GE Admiral NOS 1965 (27.5ma)
6S4A GE NOS 1962 (25ma)
6S4A Raytheon NOS 1961 (20ma)
6S4A RCA USA black plate NOS 1960's (23ma)