McVitie Weston valve collection, Ediswan valve, type V.T. No 63
Ediswan valve, type V.T. No 63, marked G.P.O. Type A, 36 V.T. No 63, serial No. 53R4, double ended glass envelope 1ft 9in overall length, 7.5in overall diam, (RMW/J111 - McVitie Weston number), by Royal Ediswan.
