This exhibit is a full wave rectifier of a type supplied to the UK armed forces before the CV system was introduced in 1941. When the CV system became operational the VU39A was re-classified as the CV1569.
The performance is close to that of the Mazda UU5.
The pair of anodes from the side.
The face view of the anodes complete with holes.
The classic envelope is 44 mm in diameter and excluding the B4 base pins, is 101 mm tall.