The CV4007 and the commercial 5726 is a miniature all glass premium quality pair of signal diodes. The design was for detector service in wide band equipment. This would typically be RADAR. The premium version is designed to be used in areas of shock and vibration such as aircraft equipment. The prototypes were the VX7129 and CV283 and the CV4007 is identical to the 5726, 6AL5W and 6097. The domestic version of these diodes was the 6AL5 and here the use was television video detector.
The two diodes are completely separate flat structures separated by a flat metal screen.
Haltron were a UK supplier of valves for export and not to the home market.
The envelope is also marked with the designations 6097, 6AL5W and 5726 showing direct equivalence between them all.
One of the small bright anodes.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 35 mm tall.
Reference: Datasheet. Type CV4007 was first introduced in 1952.