Actual pictures. NOS tube VG-236 by Ryazan tube plant. One tube or more same date.

The powerful VG-236 gastron has an oxide cathode and a metal (nickel) anode, filled with mercury vapor.

These tubes were used in rectifiers feeding small transmitters, in high-power amplifiers, and in rectifiers for high-frequency generators in induction furnaces. Manufacturers - "Svetlana", St. Petersburg (as I understand it, she is also a developer), and since 1953, the Ryazan Plant of Electronic Devices.

    

Electrical parameters:

Heating voltage - 2.5 V

Heating current - 20 A

Maximum rectified current - 4 A

Maximum pulse rectified current - 12 A

Voltage drop - 16 V

The maximum allowable reverse voltage amplitude - 7000 V

Warm-up time in operation - 5 min

Warm-up time after storage - 60 min

Ambient temperature range +15...+35°С