The CV1673 (commercially the HL2 introduced in 1931) is a receiving triode. The anode is shaped from pressed sheet that is formed with ridges for extra resistance to deforming. The CV specification says that the valve was also known as POVT105 as a GPO valve.
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 HL2 Type designation.
Through the missing metal loaded paint can be seen the side of the box anode.
A closer look.
The classic envelope is 41 mm in diameter and, excluding the B4 base pins, is 90 mm tall.
References: Data-sheet & 1040 Type CV1673 was first introduced in 1931. See also1931 adverts.
