For your consideration is this interesting figural electroform lobster pin. The only mark is 925 but it looks like the work of Bat Ami. It has a simple c clasp.
It measures 2 and 1/8 by a hair over 1 and 1/8 inches across the widest points.
It is in excellent function condition. It does have a very heavy patina that has picked up some color - I will be glad to clean if requested by purchaser.