Sterling Electric Co. fluted shaft desk set

Very rare Sterling fluted shaft with a beveled transmitter and marked back cup. Please see the scan from an original December, 1902 advertisement in Western Electrician magazine that includes this Sterling fluted shaft. The ad offers a definition from the Webster dictionary of "Sterling" - Genuine; pure; of excellent quality. It goes on to say that when you buy Silverware, you look for the "Sterling" mark. Sterling candlesticks had a very distinctive hooked transmitter mount behind the transmitter. There is also a second scan from an ad in the American Telephone Journal from 1904 and various other ads from 1904-1905.