Duplex MMCCV, uns S32205, est immaculatam ferro materia, quae trahit ejus "duplex" nomen a mixta microstucture continens roughly paribus Ferritis et Austenite. Hoc gradu est maxime popularis varietate, et hoc duo-phase materia est a significant upgrade super CCCXVI immaculatam ferro in terms of cede vires et corrosio resistentia.