The Cossor 43-IU (43IU), is an indirectly heated full wave device rectifier. Our other examples of this rectifier Type have balloon envelopes and different anode shapes. See 43IU.
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.
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. See also 1937 adverts.