The CV1154 is a directly heated triode. The commercial prototype for the specification was the PM254 and before the CV register it was known to the UK Navy as the NR16A.
The KB/D identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the D identifies the maker as Mullard Radio Valve Co., Mitcham.
The bright box anode seen from the side.
Apart from the strengthening pressed ribs of the anode, not much else can be seen.
The classic envelope is 40 mm in diameter and, excluding the B4 base pins, is 94 mm tall.
