(!!!) (Recommended Pair) 6BQ5 Sylvania gray plate NOS 1960's - 1970's (48ma and 49.5ma)1 pair) 6BQ5 Sylvania gray plate NOS, 1 tube rebranded Philips same build 1 tube) 48. 0ma Gm=10,300 Sylvania branded Philco 1960's 1 tube) 49. 5ma Gm=10,700 Philips by Sylvania 1970's Matched on Amplitrex Good mA range 40 48ma Good Gm range 10 12,000 Recommended for BLACKHEART BH5H Bad Cat Black Cat 2003 Shindo Montille RM10 Gibson GA 5 Skylark 1966 VOX Kustom