The CV1937 is an RF pentode. The prototype was the 6J7GT and the CV1937 is identical and both designations appear on the valve. The 6J7GT is etched on the glass and this indicates original manufacture. The CV Type is printed on the base shell.
The KB/T identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the T identifies the maker as British Tungsram, Tottenham.
The commercial 6J7GT. There are marks on the lower part of the glass left by the cement that once held the metal base skirt. The construction is as an all glass valve with flying leads that have been fed into the hollow pins in the plastic base and then soldered to those pins.
Looking under the outer grey screen can be seen the cylindrical anode and wire grids.
The top of the screen with the tops of the electrode supports.
Another example with the skirt in place.
The wide glass tube envelope is 28 mm in diameter, and excluding the IO base pins is 71 mm tall.
