(!!!!!) (Best Overall Pair) 311B Western Electric NOS 1956 and 1964 (35ma and 36ma)

1 pair) 311B Western Electric NOS "D" getters 1956 and 1964 same build

1 tube) 36ma and Gm=3200 (1956) original box - top cap cleaned of oxidation

1 tube) 35ma and Gm=3050 (1964) in white box

Tested on Amplitrex

Vplate=180V

Vscreen=135V

Vgrid=-15V

Good Ma = 30ma

Good Gm = 2900