The mid 1940's DAC32 is a dry battery diode triode that was designed for AM broadcast radio reception. Mullard describe this valve as a medium gain triode for use as an AF voltage amplifier combined with a single diode for signal or AVC (AGC) rectification.
The filament power is very low and consequently the valve is rated for a very low anode current.
The actual valve sections take up less than half of the inner volume. The pinch and pinch stem occupy around one third of the space. The later glass foot construction for IO based valves allowed a much shorter envelope.
The valve sections seen from the side. The gettering is on the back wall of the glass.
The wide glass tube envelope is 30 mm in diameter and excluding the IO base pins it is 82 mm tall.