The 6Q7GT is a commercial double diode triode designed for receiver audio use.
The diodes would be for signal and AGC rectification and the triode would act as AGC amplifier or first audio amplifier.
This is a miniature glass tubular implementation of the original metal enveloped 6Q7.
The anode of the triode is folded from a single sheet of nickel, stitched together and fixed to the side support. Below the middle mica is the bright screening box that shields the rods that form the diode anodes. Looking above the pinch, one can see the tape connecting the cathode to the left side support of the screening box. The rods of the diode anodes can be seen to emerge from the pinch and are shaped to run closer to the cathode.
A closer view.
The wide glass envelope has a maximum diameter of 28 mm and a length excluding the IO base pins of 70 mm.
References: Datasheet, 1040 & 1043. Type 6Q7GT was first introduced in 1936.