The CV1697 (commercially the X41) is a triode hexode mixer. The old GPO code is POVT147.
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 reverse carries the X41 identification.
Through the top of the envelope a couple of the wire grids can be seen as well as the copper wire connecting the mixer control grid to the top cap.
The classic envelope is 45 mm in diameter, and excluding the B7 base pins is 118 mm tall.
