Large Vintage Navy Tube Help

[WatchCollector56]

This large vintage navy tube was recently acquired from an estate. I was hoping if someone could tell me what it is? and its value?
Thank you!

 

[osage express]

What you have there is a type 851.
Large triode rated at 2500 volts at 900 ma. on plate in CW telegraph ratings.
Plate dissapation = 750 watts.
>From the data, I'd say it was a late 1920's jug.
I cut this from a website I think it is what you are looking for.Hope it helps