Type CV1956 is essentially the same as the commercial 6N7G quiescent push-pull double triode output valve. This valve was designed to operate in push-pull Class B2 with zero grid bias. The anode to anode load is given as 8,000 Ohm. It is capable of 10 W audio output.
Haltron is the name of a retailer specialising in selling valves outside the UK.
The triode sections lie side by side across the width of the envelope thus exposing each working face of the double sided anodes to the glass for optimum heat loss by radiation.
A closer view of the triodes. The copper grid supports are summounted by heat radiating fins for efficient grid cooling.
The classic envelope is 44 mm in diameter and, excluding the IO base pins is 95 mm tall.
References: Datasheet, 1040 & 1043. Type CV1956 was first introduced in 1936.