Detector 3335, by Sullivan, scaled 10-0-10, transistorised linear or logarithmic, 10mV, 1mV, 100microV ranges. Detector 3335 1965-1984
Sullivan type 3333 D.C. detector,10-0-10 microV dial, 1 logarithmic and 3 linear ranges, made by H W Sullivan Ltd., Orpington, BR5 3QU, serial number 712764. Sullivan type 3333 D.C. detector 1960-1979