The STC 4328D is also known by the UK government procurement code of CV245. The valve is a screened pentode based. It was used by the GPO within the telephone network and there was known as the POVT185.
This exhibit is also marked as a CV245.
The Control grid - connected to the top cap - has heat radiating fins at the top of the copper supports.
The U shape of the control grid fin.
The classic envelope is 37 mm in diameter and, excluding the IO base pins, is 100 mm tall.
