The hallmark is the German crown and crescent moon mark, next to the 835 fineness mark. Neither of them are proper hallmarks, but applied by the manufacturer.
The KU stamore possible maker? kaeser & uhlmann I'm sorry I'm new to this.. never found anythi b g like this b4 tia
Yes, Kaeser & Uhlmann would have manufactured it for Ernst Treusch. Many Treusch designs were made by others to be sold in the Treusch shop in Leipzig.
seems to be right. Kaeser Uhlmann Schwäbisch Gmünd. the jeweller Ernst Treusch was from the same city before emigrating to Leipzig; so he might have known them before he opened his shops - seems he had two. he did gold and silver jewellers works himself. this here - for me only - looks like the transitional style between Jugendstil and art déco. reminds me a bit of certain things by Chase.