The CV2453 (commercially the A2521) is a low noise UHF triode with an anode dissipation of 2.5 Watts. The advert referenced above shows that these B9A triodes were competing with the disc seal triodes such as the DET23 and DET29.
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 brand label.
The majority of the envelope is empty space.
The miniature triode is mounted horizontally. The heater wires and rectangular cathode can be seen above a gold plated plate couples to wide supports that connect to the base pins. The gold plated plate holds the frame grid. The anode sits below.
The thin glass tube envelope is 20 mm in diameter, and excluding the B9A base pins is 46 mm tall.
Reference: 1040 & data-sheet from Rob Coleman. Type CV2453 was first introduced in 1957. See also1957 adverts.
