The GZ34 is an example of a typical high current rectifier for small equipment use. It is indirectly heated but the cathode is tied to one side of the heater.
The transformer HT winding would be centre tapped. The centre going to ground. As each anode goes positive in turn the current flows, this way rectification takes place on every half cycle, and gives the name full wave.
This example from Zaerix was made in Japan
Each anode is in the form of an X with a central cylindrical cathode. The sides are asymmetrical with the longer arms having the fixing stitches.
The anode shorter sides.
The valve is of modern all glass construction with a glass foot within the base. The wires from the glass base connect to the IO base pins.
The wide glass tube envelope is 31 mm in diameter and, excluding the IO base pins, is 69 mm tall.
References: Datasheet & 1040. Type GZ34 was first introduced in 1954.