What do you make of this?

[Mike Watterson]

It's a little like a Klystron, but unlike any Kylstron I've had or seen.
The one I had looked like this WWII model:
https://www.radiomuseum.org/tubes/tube_cv35.html

Also
https://duckduckgo.com/?q=Kylstron&iax=images&ia=images

Especially https://www.radiomuseum.org/tubes/tube_cv237.html


Or perhaps an obsolete 'Backward wave tube', which are tunable microwave oscillators.
https://duckduckgo.com/?q=carcinotron&ia...&ia=images

Likely some sort of UHF to microwave device.

See also https://en.wikipedia.org/wiki/Extended_i...oscillator


Article on the first WWII Klystrons.
https://www.radiomuseum.org/forum/the_su...lator.html

Magnetrons are better known being the source today in a Microwave oven, but they are inherently pulse devices. The other kinds of UHF-Microwave devices are all amplifiers or oscillators.