These tubes are direct equivalents with US Western Electric 211 / VT4-C and Telefunken RS-237 familly. It’s a bit lower plate dissipation, but as RS237 it has metal plate which is more sonical than plates used in US 211 tubes. For best results use them in SE amplifier Ua 750V Ug-35V Ia 60ma.
Hitachi and Toshiba, the same internal structure, same plates and getters, Hitachi just have nickel base!
And above table is from Matsuda Vacuum Tube Handbook-1953.
UV-211A is not as big as US 211:
Length : 170mm – 7 7/8"
Dia: 52mm – 2 5/16"
Bulb shape T
Plate dissipation 75W
Click to see all 203 211 VT-4C triodes in stock