The CV265 is described as a damping diode or efficiency diode for recovering energy during flyback. The commercial version is the 19E2.
Later efficiency diodes used in broadcast receivers et al brought the cathode to the top cap and added more insulation between the heater and the cathode tube so that the valve could be part of a series heater chain. This valve has the cathode connected to the mid point of the heater (to avoid heater/cathode breakdown), thus the heater would be fed from a separate heater winding. This suggests that the main use was in radar displays with parallel connected heaters and driven from the AC mains.
The anodes of the two rectifier towers are joined at the top.
Face view of one section.
The classic envelope is 32 mm in diameter and, excluding the IO base pins, is 81 mm tall.
