This high voltage high power half wave rectifier can deliver 125 watts. A pair producing 250 Watts could feed a high voltage radar pulse modulator HT supply. The PIV for this valve is 14 kV.
This VU111 has the characteristic markings of an M-OV valve. Unlike some of the other versions of the VU111 this has a rectangular anode and additionally has attached fins that lead to the top cap.
The box blackened anode with multiple filament strands within.
The classic envelope is 49 mm in diameter and excluding the B4 base pins, is 125 mm tall.