set of four matching blue opalescent glass doorknobs likely designed and manufactured by or for the russell & erwin mfg co., new britain, ct. each interior residential passage size doorknob features a lightly incised sunburst pattern within the striking pressed glass handle. traces of the original silver nitrate or "mercury" interior coating remains intact. the residential doorknobs date to the 1920's. the shanks are comprised of brass with a nickel-plated finish. each doorknob measures approximately 2 inches in diameter. a total of 8 doorknob available in two lots. priced for the lot of four. salvaged from a lakeshore drive apartment building. measure 2 inches in diameter.