Material: Sen (Japanese Ash) Dimensions: Width 30cm x Depth 13cm x Thickness 2.5cm Finish: The surface in contact with food is unfinished. The edges, which tend to darken, are coated with a penetrating urethane oil (Kigatokame Ace) that complies with the Food Sanitation Act. ☆ After use, wash, wipe off moisture, and dry in a place away from direct sunlight. ☆ Please be aware that kitchen bleach may react with the wood components and cause blackening. ☆ As this is made of wood, avoid soaking it in water for extended periods. ☆ Avoid using in dishwashers, microwaves, and ovens. * Sen is a deciduous broadleaf tree that grows naturally throughout Japan.