Cossor 210-DDT double diode triode for battery operation

The 210DDT is a double diode triode designed for battery-operated broadcast receivers. Normally such a valve would be placed at the end of the IF amplification in a superhet receiver. The triode would act as the audio voltage amplifier with the diodes acting as a signal demodulator and AGC rectifier. The classic envelope is 44 mm in diameter, and excluding the B5 base pins is 106 mm tall.

The 210DDT was first introduced in 1938.