This exhibit is one of a pair and neither has adequate markings for a firm identification. The only visible lettering etched into the envelope is 5S23V007A. From our other 5S we know that the lettering says 5S 2.3 V 0.07 A
Inside the magnesium gettered mirror envelope it is difficult to see the construction. But what is visible is a horizontal cylinder anode with a small diameter grid. The grid appears to have end caps and the grid wire proper is not revealed.
The wide glass tube envelope is 40 mm in diameter and, excluding the B4 base pins, is 82 mm tall.
Updated May 02, 2013. shape:wide.glass.tube construction:pinch type:triode age:1920.1930 base:b4 pins:4 pin:1.a pin:2.g1 pin:3.f pin:4.f