A bowl-shaped pan that is used to quickly cook food over high heat. It is available with a rounded or flat bottom. The traditional type wok has a rounded bottom and is used over a flamed heat source, such as a gas burner. The flat bottom wok was designed to use on an electric burner or a ceramic stovetop but can also be used on a gas stove. The rounded woks come with a ring that should be placed over the flames to hold the woks steady. Woks are available made from various materials, such as carbon steel, cast iron, stainless steal with aluminum inner layers, and metal with a non-stick coating applied. Cast steel and cast iron woks must be seasoned before they are used for the first time. The wok is most often used for stir-frying but can also be used for sautéing, steaming, deep-frying.