The Hookah Potato Head Bowl is made of durable clay material and comes with 1 thick silicone grommet. It is made of unglazed clay. It's around 3" tall.
Traditional unglazed bowls are free of glaze. Glaze is used on bowls mostly for aesthetic reasons and to prevent the bowl from absorbing the flavor of the shisha. Lot of glazes on the market are lead based and can be hazardous. If you are not certain then this hookah bowl is the safest to use.