Cooks foods in half the time. These 2 T304 stainless steel pans - 9qt and 4qt can be used 2 ways: One can be turned into a low pressure, pressure cooker with the addition of the pressure cooker lid and the welded, riveted handles locked into position; or, either pan can be used as a standard cooking pan with the addition of the "see-thru" glass cover not locking the handles. What does low pressure cooking mean? It is convenient and safe because you can open and close the lid anytime to check what you are cooking or to add ingredients. Limited lifetime warranty.