The PCF80 is the definitive triode pentode mixer/oscillator from the dawn of Band III television in the mid 1950's. Originally Band I television operated around 45-50 MHz but with Band III the working frequency moved to 174 - 240 MHz and new valve techniques were demanded.
The glass is also marked with the designation 9A8.
The pentode on the left has a cooling fin on the control grid supports.
The triode seen face on, it also has copper support rods for the grid.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 49 mm tall.
References: Data-sheet & 1040. Type PCF80 was first introduced in 1953. See also1953 adverts.