The item is labeled "BURNER select Big Ring". Color: 27 Size: 7 The size is likely US size. The diameter is approximately 17mm, which is close to size 14 in Japanese sizing. It's a men's ring, but it seems to be a small size. Unused item. The brand is unknown. Purchased from ZOZO. (The sticker on the item at the time of purchase said "BURNER select Big Ring.")