(!!!!) (Best Pair #2) 6F8G Sylvania and Sylvania Zenith parallel black ribbed plates like new 1940's (8.2/7.8ma and 8.0/7.0ma) 1-3% matched (very close Gm)

1 pair)  6F8G Sylvania and Sylvania Zenith parallel black ribbed plates like new 1940's in white boxes

1 tube) 8.2/7.8ma Gm=2500/2500 Sylvania Zenith

1 tube) 8.0/7.0ma Gm=2600/2500 Sylvania

plate structure and internals are the same as VT-231 Sylvania

Tested on Amplitrex

Vplate=250V

Vgrid=-8V

Good Iplate = 7-10

Good Ma = 2400-2600

NOTES:

6F8G = (2) 6J5G inside 1 bulb

1 section has top cap for grid

1 section has internal grid connection

GE, Sylvania and Raytheon have mirror image parallel black plates

RCA and Ken Rad have staggered black ribbed plates