This Cossor rectifier, 43-IU (43IU), is a full wave device with a directly heated oxide coated ribbon filament. Our other examples of this rectifier Type have balloon envelopes and different anode shapes. See43IU.
The two perforated anodes have a wide face and small front to back dimension.
One anode face view. The indirectly heated cathode sits in a cylindrical cavity at the centre of the anode. With the balloon style envelope versions the rectifiers are directly heated with coated ribbon filaments.
The top mica, the hairpin heater can be seen and the two cathodes are both connected to the central support.
A closer view of the construction.
The classic envelope is 45 mm in diameter, and excluding the B4 base pins is 104 mm tall.
References: 1040 & 1043. Type 43IU was first introduced in 1937.