The 35Z5 is a half wave rectifier for heater chain service. The maximum reservoir capacitor is 40 μF and the surge limiting series resistance must be at least 100 Ohms.
The heater is tapped to allow a dial lamp to be wired in parallel with a portion of the heater. The lamp lasts longer as the surge is reduced and the radio continues to work with a broken dial lamp.
The anode has a small front to back dimension.
Face on the anode is broad and the plates are fixed together by punching rectangular holes in one plate and pushing lugs formed in the other plate into the holes and then folding them over to lock them.
The wide glass tube envelope is 27 mm in diameter, and excluding the IO base pins is 68 mm tall.
References: Data-sheet, 3002 & 1040. Type 35Z5GT/G was first introduced in 1939.