The PM84 is a tuning indicator for use on 300 mA heater chain systems. So for use on sets that can be used on Ac or DC mains. The all mains version is the EM84.
The side facing screen. Increasing signal strength would be indicated by ever longer green bars growing together until they overlapped.
The amplifier triode is mounted horizontally. The heater is coiled and insulated.
The side mica sheets hold the triode grid behind the cathode with the deflector electrode placed closer to the screen.
The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 65 mm tall.
