The CV4503 is a miniature pentode with flying leads for direct wiring into a circuit. The operating parameters give a frequency of 50 MHz.
The KB/DC identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the DC identifies the maker as Mullard Radio Valve Co., Whyteleafe.
The face of the anode.
The side of the anode is open and the three wire grids can be seen. The internal connections from the base are made in copper.
The thin glass tube envelope is 10 mm in diameter, and excluding the base leads is 37 mm tall.
Reference: Data-sheet. Type CV4503 was first introduced in 1960. See also1960 adverts.