This CV242 photocell exhibit is designed to have an anode voltage of 90 Volts and has a sticker to indicate this. Other examples have anode voltages of 80 Volts.
The KB/OR identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the OR identifies the maker as Rank Cintel, Rotunda.
The half cylinder photo-cathode and ring anode.
Face view: the coating is crazed.
The thin glass tube envelope is 26 mm in diameter, and excluding the B4 base pins is 86 mm tall.
