The 6D2 is the Mazda equivalent of the Mullard EB91, and consists of two separate signal diodes in the envelope.
The diodes were designed for vision and sound detection in television receivers. Additionally they are recommended for limiting and DC restoration.
The 6D2 was used in the 1948 Murphy television receiver V114 as a frequency changer.
The two diode sections with the central screen. The embossing adds strength to the thin sheet metal of the screen.
One diode; the two sides of the anode are stitched together leaving a cylindrical hole in the centre for the indirectly heated cathode.
This thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 47 mm tall.
References: Data-sheet & 1040. Type 6D2 was first introduced in 1953. See also 1953 adverts.