Cool deco German ring - help ID the stamp?

[racheldelancey]

Got this cool deco ring at an antique market in Berlin! Think it’s steel or silver but has this cool mark on inside wondering if anyone recognizes it as a makers mark!

 

[VRBeauty]

This might be a good starting point for you. Good luck!

German Hallmarks - Encyclopedia of Silver Marks, Hallmarks & Makers' Marks