(!!!) (BEST PAIR) 485 National Radio tube engraved base mesh-plate NOS 1930's (6.0ma and 6.4ma) (variant of 27)

1 pair) RX-485 National Radio tube engraved base mesh-plate NOS 1930's

1 tube) 6.0ma and Gm=1200

1 tube) 6.4ma and Gm=1200

(485 is a variant of Type 27 with 3V @ 1.25A filament)

(Sparton=The Sparks-Withington Co., Jackson, MI)