Ross may pipe up and say where he got a pic of that but it is some kind of transmitting tube.
Air cooled I think ?
The big round top (upside down) is the plate for pretty sure and the bottom (right side up) ring might be a connection ?
If this is a directly heated cathode triode tube then the 3 wires sticking out the bottom would be heater-cathode, heater-cathode and grid.
boB