Purchased from an antique shop over 20 years ago. It is said to have been used as a signal in Buddhist memorial services and tea ceremonies. It produces a loud, pleasant sound. There are scratches, dents, and rust. There is a small cut in one place (photo 10). A magnet does not stick to it. There is also verdigris, a type of rust. It is probably made of copper. Diameter: Approximately 22.5 cm Thickness: Approximately 4 cm Weight: Approximately 550g For those who understand the nature of old items, Thank you in advance.