This product is made by joining finely-grained Kiso Hinoki cypress wood to prevent warping, resembling a single board. The sides are rounded inward for easy handling and to prioritize water drainage. It is urethane coated to reduce mold. Kiso Hinoki cypress has a moderate softness, which helps blades stay sharp longer. Dimensions: 19cm (length) x 31cm (width) x 22mm (thickness) Thank you for viewing.