The 6AL5 is a double signal diode. Pope became a brand of Philips.
The two valves are completely separate flat structures separated by a plate screen. This clearly shows the signal usage, where it is important to keep RF isolation.
These double diodes were designed for sound and vision detection in 405 line televisions. Additionally they are recommended for limiting and DC restoration, again part of a TV receiver functionality.
The two diode sections with the electrostatic screen between them.
The small central cathode tube surrounded by the heat dissipating wings of the anode.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 37 mm tall.
References: Data-sheet & 1040. Type 6AL5 was first introduced in 1945. See also1945 adverts.
