This CV582 is an RCA 6C5 with the UK CV designation overprinted on it.
Type 6C5 disappeared from the lists fairly early because it was superseded by the 6J5 which had slightly superior ratings and characteristics but was, for all practical purposes, a direct replacement.
Most 6C5s were of the metal-envelope type whereas most 6J5s were 'GT/G' and therefore suitable for a wider range of applications. NB. Type 6SN7GT is two independent 6J5s in one envelope.
The RCA logo and Made in USA on the left edge.
The lettering when manufactured included both the 6C5 and the US Service designation of VT-65.
The thin metal tube envelope is 25 mm in diameter and, excluding the IO base pins, is 51 mm tall.
