A rare sonor style telescopic French ear trumpet made from faux mother-of-pearl

These oval shaped French ear trumpets were popular in the early 20th century. The ear piece could be extended from the top of the body resulting in a function aids which was just small enough to be portable.  They usually come in a form of a russet or tortoiseshell celluloid and I have not seem one in this material before.  The combination with the ornate gilt brass grille it gives a visual feast.