The CV4025 is the UK Government procurement specification and the commercial equivalent is the 6058 and the prototype was the CV140. This special quality double diode is based on the 6AL5. These diodes are for signal rectification at medium frequencies eg. video.
The KB/Z identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the Z identifies the maker as MO Valve Company, Hammersmith.
The GEC paper brand label. M-OV used the GEC brand for items intended for professional end use.
The /Z make identifier. One of the diode sections. The heater is a single inverted V made with a single strand of insulated wire.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 46 mm tall.
