The Ediswan 6D2 consists of two separate signal diodes in the envelope and is identical to the 6AL5 double signal diode..
The diodes were designed for vision and sound detection in television receivers. Additionally they are recommended for limiting and DC restoration in television receiving equipment.
The 6D2 was used in the 1948 Murphy television receiver V114 as a frequency changer.
The anode plates are stitched together and held between mica discs. The centre plate is the electrostatic screen.
The top of the envelope is used only to house the getter holder
This thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 45 mm tall.
References: Data-sheet & 1040. Type 6D2 was first introduced in 1953. See also1953 adverts.