(!!) (Best Pair #2) 6GM5 Sylvania branded RCA NOS (52ma and 52ma)

1 pair) 6GM5 Sylvania branded RCA NOS 1970”s

1 tube) 52ma Gm=9800

1 tube) 52ma Gm=9650 no printing – on right

Tested on Amplitrex

Good Current Range = 50-60ma

Good Gm range = 9500 – 10,000