Type 6SC7GT is the glass tubular implementation of the original 6SC7 metal enveloped valve.
It is a double triode and the design was superseded by the 6SL7 in the early 1940's.
The internal coating obscures most of the double triodes but at the top they can be seen to consist of a cavity for the cathode and grid and a side wing with the stitches and the support rods.
The dome and top mica. The streaks in the coating are where the pre-formed electrodes have been inserted into the envelope.
The wide glass tube envelope is 28 mm in diameter, and excluding the IO base pins is 61 mm tall.
