In my mail is a Gruen version of the Waltham Opera watch that was from before 1900. Have seen only 2. This non-Gruen probably 1911 when Watch Specialties first used. Also marked DG&S which is latest I have seen. Even on dial which is only p.w. I have seen with only that mark. Seller photos and my same w.w. 3/0s mvt. here. I expect Dietrich who died 1911 would not have allowed this one to be made, and it uses marking other than Gruen, that normally indicated high quality this cheap one is not. Not really cheap because this was a very popular 15j adjusted movement in many w.w. and pendant cases. Bet it had a short production life. Showing a friend's best Waltham version.