The 6AL7GT is a CRT type tuning indicator for accurate tuning of FM or AM radio receivers. The screen is in the top of the envelope and two rectangular green blocks are controlled by three deflection electrodes.
The Sylvania name and Made in USA.
The Sylvania logo. The electrodes are mounted horizontally and the cathode connection can be seen passing to the left.
The IO base on this unused valve.
The central oxide coated cathode tube with the single sided control grid passing in an arc above it.
The two part rectangular end window.
The curve of the grid is clearer in this image.
The grid has been wound around the supports and later one side has been shaved off.
The wide glass tube envelope is 28 mm in diameter, and excluding the IO base pins is 56 mm tall.
Reference: Data-sheet. Type 6AL7GT was first introduced in 1946. See also1946 adverts.
