The VU120 is nominally equivalent to the SU2150A from Cossor. Both Mullard and M-OV manufactured EHT rectifiers to this specification but in each case the valves were redesigned to suit factory production methods. The UK Navy insisted on the 'real thing' from Cossor as design proved to be the best performing over time.
The maximum reservoir capacitor is 0.25 µF, and the minimum series resistance is 10 kOhms.
The anode cylinder is held in glass supports and connected to the top cap the diameter is large to allow adequate separation between it an the oxide coated cathode.
The cathode is held in place with two supports in parallel to the top mica.
The classic envelope is 47 mm in diameter at its widest and excluding the B4 base pins the valve is 111 mm high.