Heintz and Kaufman Gammatron 24G (VT204) VHF triode.

The valve measures 110x35mm, plus a further 15mm for the side connector. It has a 4-pin base, the grid is connected to the side connector and the anode to the top.

This valve carries the markings 24G and US Army VT204. It has the serial number 15482 marked on the glass.

Also known as 3C24, 25TG, CV745, this valve has a thoriated tungsten filament rated at 6.3V/3A, µ of 25, 25W output.

See also 24 which is a similar valve but without the grid connector at the side.