Hi there I recently aquired this at a garage sale at the bottom of a box below some clocks. Its a stamp of some sort made of Steel I believe. This plate is 1 inch thick and 4 in tall and 2 1/2 wide. The plate is of a anchor wrapped by a chain with the letters U.S.N. embroided on it. Does anyone know what this is for ,or have any info at all about it?