Materials: In many cases, Japanese cedar (such as Kiso Japanese cedar), which has excellent moisture absorption and release properties, is used. Hoops: The metal rings that tighten the circumference are called copper hoops, which increase durability and are also expected to have antibacterial effects. Role: Because the wood absorbs excess moisture, the rice does not become sticky and results in glossy, delicious sushi rice. Diameter: Approximately 29 Height: Approximately 9