D.R.G.M. Brass Chain Link Ring Frame Horizontal to Vertical

Circa 1890s convertible Brass Frame marked "D.R.G.M." on the back. Measures approximately 7 1/2" X 5 3/4" overall; photo/glass area approximately 4 1/4" X 6 1/2"--it originally held a Cabinet Card photograph. It has a swivel mechanism on the back that allows the easel to fit in either the horizontal or vertical position. I have not seen or had this pattern of chain links or rings before in a marked DRGM frame. D.R.G.M. is a German registry mark used from 1891-1949; then it became DBGM. The original beveled glass is there, but has minor chips and flakes---it is hard to find these frames with their original beveled glass inserts, so I left it--you can certainly have new glass cut by your local hardware store if you choose. Other DRGM frames available on my site--enter D.R.G.M. [include periods] in my search box.