M'héritage , copper and stainless steel. All M'héritage products are 90% copper and 10% stainless steel. The combination of copper and stainless steel make up the thickness in both collections. - M'150 collection consists of a 1.5mm thickness and the M'250 is a professional thickness of 2.5mm. The difference is in the makeup of the handles, cast iron, bronze or cast stainless steel, giving each of us an opportunity to decide our style.Marvel Heritage is used all around the world both by professional cooks and home chefs.