stainless steel hex nut 1.material:mild steel,45# steel,40Cr 2.surface:zinc plated,black oxide.... 3.size:M8- ... M42 4.grade:4. Material mild steel,45# steel,40Cr steel Surface inc plated, black oxided,phosphated Size M8-M42 ... by your design.Other services can be consulted in dealing. stainless steel hex nut