The EMM803 is an unusual, tall magic eye tube with a dual display. The two displays are in line rather than side by side as in the EMM801. The upper the quarters of the display has a conventional tuning indicator display (similar to the EM84) with two bars that converge in the middle. The bottom quarter of the envelope has a single short bar which rises and falls from the bottom. Normally the tube would be used with the top part showing tuning and the lower part showing level or as a stereo indicator.
The heater requirement is 6.3 Volts at 0.45A and the HT is 250-300 Volts. The EMM803 and the EMM801 are now rare items.
Looking into the screen, the two columns would be formed along its length.
A side view mainly showing the two cathode tubes and heaters.
The side window envelope is 20 mm in diameter, and excluding the B9A base pins is 71 mm tall.
Reference: Datasheet. Type EMM803 was first introduced in 1963.