This exhibit is clearly a professional valve but has lost all identification. The condition seems to be new and it has just three connections and thus is a rectifier. The active region is enclosed and it is possible that the anode is also connected to the lower disc and supports around the pinch. If this is the case the filament is totally enclosed. This suggests an EHT device with protection against X-Ray radiation escaping.
The filament connections pass into the enclosed area through ceramic insulators.
The pinch stem with the nut and bolt fastener.
The top cap and the bell of the anode.
The Giant Edison Screw base.
The wide glass tube envelope is 57 mm in diameter, and including the base is 240 mm tall.
Updated December09, 2017.