The CV1988 is the UK government Common Valve version of the 6SN7GT double triode valve. Each half of the valve is electrically equal to the 6J5 triode.
Unlike CV1988 these triode sections have rectangular box anodes. Normally the 6J5 family are made with rounded anodes.
Each triode anode is stitched together forming a flange and clamping the support rod.
The wide glass tube envelope is 28 mm in diameter and, excluding the IO base pins, is 68 mm tall.
References: Data-sheet, 1040 & 1043. Type CV1988 was first introduced in 1941. See also1941 adverts.
