The DET16 is an HF amplifier triode for use up to 30 MHz. It may also be used in Class B as a zero bias amplifier where an output of 350 Watts may be obtained from a pair.
Terry Collard had annotated this valve with the fact that it was used in an early warning Radar. The radar is in the Science Museum London.
The high voltage is indicated by the ceramic insulators and the valve dissipation of 125 Watts requires a graphite anode. The bayonet base requires a locating pin and this can be seen on the left of the base.
The lower insulator with graphite anode above.
Another view of the lower insulator and structural support. The grid is wound as a box
The wide glass tube envelope is 64 mm in diameter, and excluding the base pins is 226 mm tall.
Reference: Datasheet. Type DET16 was first introduced in 1954.