These appear to be vintage U.S. Army Warrant Officer 2 insignia pins featuring brown wood or cloisonné inlay.

They are constructed with a shiny metal base, likely sterling silver or plated nickel, and are designed for wear on shirt collars.

Similar items have been identified as dating from the 1950s or the Vietnam era.

This mark indicates a sterling silver item produced by the manufacturer E.H. H. Simon Inc.

E.H. Simon Inc. (often marked as EH SIMON INC NYC or SIMON-G.I.) was a prominent American manufacturer based in New York City that specialized in producing high-quality military insignia, badges, and government service pins from the post-World War II era through the mid-20th century. 

If you own a silver item stamped with this name, it is almost certainly a piece of United States military or federal heritage. 

Chief Warrant Officer 3 (CWO3): A silver-framed bar featuring blue enamel (for the ⁠Marine Corps or ⁠Navy) or brown enamel (for the Army). E.H. Simon examples are highly documented for this specific rank