7 layers of all-over sandwich aluminum with excellent heat conductivity Consistent thermal efficiency throughout saves heat energy and reduces cooking time. The Geo Products are constructed with a tight seal between the body and the lid. In addition, the lid has a moderate weight and does not have a steam hole, so when heated, the moisture inside the pot becomes water vapor and creates a water membrane (water seal) between the main unit and the lid to seal the pot. Since it can maintain its near constant temperature and constant pressure, it is possible to "waterless cooking" and "preheating" cooking.