I can't find a tag on mine but a repair manual says a General Phonograph Mfg. Co. Elyria, Ohio and a Schwarze Electric Co., Adrian, Mich. I hope this helps.
Where Are You From? Grand Rapids, MI
Do You own a car built by Durant? 1923 Star, 1928 Durant
That will help, I'll search those names. In the meantime I just purchased an EA Labs "Premiere" on Ebay. It's a motor horn and will probably work just as well.
Hi Don. I also found no I.D.. plate on my horn. The Nov. 22 parts book gives a part no 20415 made by the General phonograph MFG co, of Elyria Ohio, I hope that this info helps Bert