... alloy steel,Japan SUH660,America A286,35#,40CR,35CRMO,SCM435,Brass,and etc. Camera ScrewSurface treatment Plain, Black Oxide,nickel plated, ... , passivated, zinc plating, phosphated, Dacromet,copper plating, gold plating and etc as per your need. Camera Screw salt spray time ... test, mechanical sizes test, ROHS report Mill test certification and etc as per your need. D.Factory general impression Factory ...