The PCL83 is a television triode output pentode with a main role as frame oscillator and output stage and a secondary use as an audio stage.
The glass is discoloured indicating a hard life for this exhibit. The three wire grids of the pentode can be seen as can the edge of the triode grid on the right.
A closer view of the sections.
The thin glass tube envelope is 20 mm in diameter and excluding the B9A base pins, is 48 mm tall.
References: Data-sheet & 1040. Type PCL83 was first introduced in 1954. See also1954 adverts.