Price is for 2 NOS tubes in what was SEALED box before I have opened it for taking pictures. Produced in England before 1955 (proven by the etched codes 1185). Construction with black anodes, gray-coated glass inside and brown bases. One of the tubes is in-face very early prodcution. Quite rare.
Test GOOD as follow:
Tube 1
Ia1 = 5.9 mA | S1 = 2.3 mA/V | Ri1 = 14.0 kOhm | μ1 = 32.2
Ia2 = 5.7 mA | S2 = 2.1 mA/V | Ri2 = 14.8 kOhm | μ2 = 31.1
Tube 2
Ia1 = 5.4 mA | S1 = 2.2 mA/V | Ri1 = 15.1 kOhm | μ1 = 33.2
Ia2 = 5.2 mA | S2 = 2.3 mA/V | Ri2 = 14.1 kOhm | μ2 = 32.4
Test under: Uh=6.3V | Ua=250V | Ug1=-4.6V
Shipping will be Airmail registered with tracing number. Other shipping methods available on request.