The PCF806 is a triode and frame-grid pentode frequency changer for VHF television receivers up to 220 MHz.
The local oscillator is based on the triode and the mixer is the pentode. The heater rating is precise and so can be used both in series or parallel configurations.
Another example of the PCF806. The triode is on the left.
The triode is on the right. The copper rod (left foreground) is the pentode screen grid connection.
The gap in the side of the anode reveals the wire suppressor grid, indicating a true pentode.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 41 mm tall.
