McVitie Weston valve collection, Marconi valve, type D.E.T.1.S.W.
- maker:
- Marconi Company Limited
Marconi valve, type D.E.T.1.S.W., marked 810T, stem marked 8503, bi-conical glass envelope with square black moulded 4-pin MOV base at one end, anode cap at other, filament missing, (RMW/J36 - McVitie Weston number), by Marconi Company Limited.