The experimental E4103/B/4 small CRT from GEC was later renamed the 401A.
Both anodes are connected together and need 1,000 Volts on them. With 1,000 Volts on the anodes the Y sensitivity is 0.09 mm/V and the X sensitivity is 0.1 mm/V. The grid voltage of -25 Volts is to achieve cut-off. The screen has a green trace.
The paper label has been stuck to the glass with clear adhesive tape - now yellowed with age.
Stating the obvious?
The serial number is 11031.
The X deflection plates can be seen entering the region of the envelope where the Aquadag colloidal graphite coating covers the inside of the glass.
The B9 bas pins.
The end window envelope is 38 mm in diameter, and excluding the B9 base pins, is 140 mm tall.
References: Datasheet & 4018. Type E4103/B/4 was first introduced in 1936.