McVitie Weston valve collection, valve, type 230D (Exptl)
Valve, type 230D (Exptl), cylindrical tube 2.5 in diam x 14.5 in long with longitudinal evacuating pip, two-ended with a single lead at one end and 10 flying leads at the other, (RMW/Y399 - McVitie Weston number), by Unknown maker.