Three Schwartz thermopile infra-red detectors, by English Electric Co. Ltd., England, 1950. Three Schwartz thermopile infra-red detectors 1950
Infra-red detector with brass housing and lead telluride, with spare detector, (initial callibrations included), British, made by Mullard, 1949-1959. Lead Telluride Infra-Red Detector, 1949-1959 1949-1959