McVitie Weston valve collection, STC Micromesh valve, type H.L.A.2.
STC Micromesh valve, type H.L.A.2., glass envelope cracked, (RMW/F56 - McVitie Weston number), by Standard Telephones and Cables Limited.
STC Micromesh valve, type H.L.A.2., glass envelope cracked, (RMW/F56 - McVitie Weston number), by Standard Telephones and Cables Limited.