Technical Trading were a re-seller of valves and equipment. This exhibit has been re-branded but looks much like a Philips made PL83. The groove in the join between the hard glass base and the soft glass envelope is typical of Philips machinery.
The PL83 was designed as a sensitive video amplifier valve for television receivers.
The discolouration inside the glass speaks of a hard service life.
Each side of the control grid support rods is mounted a small radiating fin to cool the grid.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 69 mm tall.
References: Data-sheet & 1040. Type PL83 was first introduced in 1951. See also1951 adverts.
