Royal Ediswan valve, type R, brass and ebonite 4-pin base, top pip, anode out of place, (RMW/B126 - McVitie Weston number), by Royal Ediswan. Very early and rare R-type with 11-turn grid and no supports. Has large brass base 38mm high and ebonite (black) cap and split pins. Spherical bulb, pip top, no getter, platinum seals.

This is a very early and rare Royal Ediswan R-type triode radio valve first introduced in 1922 and used in early radio broadcast sets in the 1920s