The CV589 (commercially the 6Q7GT) is a double diode triode and was designed for receiver use.
The diodes would be for signal and AGC rectification and the triode would act as AGC amplifier or first audio amplifier.
The KB/FB identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the FB identifies the maker as STC, Footscray.
The triode at the top with the diode anode screen below. The diode anodes are plain vertical rods and can be seen as the angled wires between the filament supports and the screening box supports. The screen is connected to the cathode by the wire on the left.
Side view.
The reverse showing the stitched anode and the spot welds holding the triode anode to the supports.
The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 70 mm tall.
