The 6K7G is a screened pentode and was designed for intermediate frequency amplifiers in superhet receivers. It is high impedance type allowing for a high Q in the tuned anode circuit.
The base has a stores code of ZA5699 stamped into it and inked yellow.
The pinch stem with evacuation tube attached. The cathode looks to be connected to one side of the heater but in fact the connection passes behind to the centre support in the pinch.
Looking up beyond the lower screening disc the perforated outer screen is seen to pass close to the anode cylinder. Three wire grids and the white of the cathode complete the picture.
The classic envelope is 38 mm in diameter and, excluding the IO base pins the valve is 97 mm tall.
References: Data-sheet, 1040 & 1043. Type 6K7G was first introduced in 1936. See also1936 adverts.
