This Australian-made educational CRT is mounted on a locally built power supply and was used in lecture demonstrations.
The tube visualises how an electron beam can be deflected by the electric field between parallel plates. In fact a ribbon-shaped beam is used, that grazes an inclined phosphor screen to produce a glowing line, demonstrating how the beam in an oscilloscope tube is deflected.
A magnet has been provided so that the lecturer can also show the deflecting effect of a magnetic field (used in television tubes).