The paper outlines some of the tremendous number of applications where Duplex stainless steels are used in several industries. It explains also why Duplex alloys are cost competitive by possible weight savings due to their high mechanical properties. Furthermore, 5 to 20 years in service experiences show that they are also cost savings, due to lower maintenance costs. Experiences in Europe, Far East, America and Africa are reported. They concern pulp and paper, chemical (organic and inorganic), petrochemical industries as well as pollution control equipments (FGD), off-onshore, ship building applications, or even, art !