6 × 6 × 12.7 cm

This valve is a VHF air-cooled tetrode. It has a thoriated Tungsten filament. It is mounted with the fins pointing downwards. Forced air cooling is required, through the fins upwards, with the air directed over the envelope and base pins.

The CV number indicates that this valve was made for the military forces.

The code 7421 on the glass indicates the valve was made in the 21st week of 1974.