This exhibit is a British made GZ30 full wave rectifier. The GZ30 was designed for larger domestic equipment and audio amplifiers. The maximum reservoir capacitor was 50 µF and the minimum effective series resistance had to be 380 Ohms. The maximum peak inverse voltage was 1.4 kV.
The two anode sections mounted side by side.
Face view of one anode.
The wide glass envelope is 28 mm in diameter and, excluding the IO base pins, is 69 mm tall.
References: Datasheet, 1040 & Alf Parker. Type GZ30 was first introduced in 1940.