Sai Engineering Company manufactures Highly Polished Die & Nozzles within a T.I.R. Of 0.01 mm. [.0005 inches]. The Die & Nozzles are highly polished to ensure an even flow of the material. The standard material for highly polished Die & Nozzles is [depending on applications]: D-2 [Die Steel] H-13 [Hot Die steel] and stainless steel.