This item is made with ultra-durable lava rock, sourced from the rare Fuji-Hakone-Izu National Park. It was featured on the TV show "Buratamori," where Tamori-san mentioned using one at home. A major feature seems to be that it allows for cooking with minimal smoke. Diameter is 25cm, thickness is about 2cm. The thickness is 1.8cm. This is a new, unused item, stored at home.