(!!!) (Recommended Pair) 12B4A GE NOS 1960's (32.5ma and 33ma)
(!!) (Recommended Pair) 12B4A GE NOS 1960's same build (32.5ma and 34ma)
(!) (Recommended Pair) 12B4A Sylvania NOS 1960's (26ma and 27ma)
(!) (Recommended Pair) 12B4A Sylvania NOS 1970 era (26ma and 26ma)
