The VT-126B American Government specification is equivalent to the commercial 6X5GT/G. The 6X5GT/G is etched into the side of the envelope and the VT designation is printed on the base.
It is a standard HT rectifier for low power AC mains driven equipment and the design was produced by several manufacturers. The original 6X5 design dates from 1936.
The output of a centre tapped transformer would be applied to the anodes, the rating given is 325-0-325, the common cathode would be the output for the rectified voltage. A effective series resistance of 350 Ohms was required to limit surges and the reservoir capacitor had to be restricted to 16 µF.
The pair of anodes seen end on. Both are full height and one side of each radiating section passes close the other anode making it look like a half wave rectifier at first glance.
The right hand anode has a semi cylindrical section around the cathode and its left hand edge is fixed into the micas half way along the left hand anode.
The wide glass tube envelope is 29 mm in diameter, and excluding the IO base pins is 61 mm tall.