This small precision electrostatically deflected oscilloscope tube has a 32 mm face and an 11 pin special base. Such small instrument tubes were used for waveform monitoring rather than in traditional oscilloscopes.
The components of the electron gun and electrostatic lens are held in glass side rods that have been melted around the side tabs of the plates.
The screen shows no sign of phosphor burns and this tube is probably new old stock.
The lens plates have four support tabs and only two are secured in glass. Here we see the unused tabs. On the left, before the aquadag colloidal graphite inner coating, can be seen the Y deflection plates. The less sensitive X plates are closer to the screen.
A closer view of the Y plates.
The end window envelope is 32 mm in diameter, and excluding the special base pins is 92 mm tall.
Reference: 3002. Type D3-130GH was first introduced in 1976.