The silversmiths firm Wilhelm Binder were founded in Schwäbisch Gmünd, Germany in 1869.

Conclusion: Looking from left to right.

1) The Half Moon and Crown symbol is the sign for made in Germany after 1884, and was compulsory

2)  800 means the standard of silver is 800/1000

3) The letters WTB are the letters that symbolize the firm Wilhelm Binder.

Summary:

This is a hallmark of a piece of 800/1000 silver, made in Germany after 1884, by the silversmith firm Wilhelm Binder in Schwäbisch Gmünd.