The 3B22 is a xenon arc full wave rectifier. It features tantalum anodes for high temperature operation. The rectifier is rated for a current of one Amp and a peak inverse voltage of 725 Volts. Normal anode voltage would be between 12 and 250 Volts.
The filament runs at 2.5 Volts and this was the first American standard voltage for mains valves.
Visually The construction is very different to our other 3B22.
The central mesh is the top end of the oxide coated filament.
The pinch end showing the lower end of the folded mesh filament.
The wide glass tube envelope is 40 mm in diameter, and excluding the UX4 base pins is 119 mm tall.
Reference: Datasheet. Type 3B22 was first introduced in 1953.