Mai jos este o descriere de pe "The Valve Museum".

The PCC189 is a low impedance high gain double triode. The technical specification specifically states that it is built with frame grids. The valves are variable μ types for use at RF as AGC controlled devices. The low voltage high current suggests a low noise design, probably as the front end stages in a television tuner. The low anode voltage suggests both stages used as a cascode (series connected) amplifier.

Mullard describe the PCC189 as: a VHF variable-mu frame-grid cascode double triode.

The working face of the anode is at the end of the depression, the rest is heatsink.

The thin glass tube envelope is 20 mm in diameter and excluding the B9A base pins it measures 50 mm tall.

Dario Miniwatt RTC o parte din ele par a fi facute de Philips in Heerlen facute in 1965 iulie iar un tub (cel din mijloc) de Mullard in Blackburn 1965 aprile.