This valve is marked as a CV but was manufactured as a PM22. The PM22 output pentode itself dates from 1928, and was designed for battery operation. It clearly was still effective in 1941 when the CV system was introduced for service valves.
The filament and anode voltages are printed onto the top of the envelope together with the type designation.
The anode load impedance required is 8,000 Ohms.
This valve was made in both four and five pin versions, the connections are for the five pin version.
The balloon envelope is 47 mm in diameter and, excluding the B4 base pins, is 88 mm tall.
References: 1931 data-sheet & 1043. Type CV3649 was first introduced in 1928.