Chinese bronze mirrors were made for well over two thousand years, and the decorated side — the reverse — is what has survived in good condition, because the polished face corroded. This piece reproduces the decorated reverse: a central boss with a cord hole, and concentric rings of cast motifs.
It is not a mirror. The face is not polished to a reflective finish and it will not give a usable image, which is a common misunderstanding with pieces of this kind. Solid brass with an antique patina, on a hanging cord.