This Cossor rectifier, 43-IU (43IU), is a full wave device with an indirectly heated cathode that is tied to one side of the heater.
The lettering on the dome carries the maker's name and codes but not the Type designation.
The twin anodes above the mica and below the cathode wire connects to one side of the heater.
The dome with everything but the Type designation. Note the oval cathode tube poking through the top mica.
The classic envelope is 49 mm in diameter, and excluding the B4 base pins is 114 mm tall.
References: 1040 & 1043. Type 43IU was first introduced in 1937. See also 1937 adverts.