... steel camera screws size: M3-M6 D=2-4mm camera screw head shape:with a D ring camera tripod screws :A.Product specifications ... steel,Japan SUH660,America A286,35#,40CR,35CRMO,SCM435,Brass,and etc. Camera ScrewSurface treatment Plain, Black Oxide,nickel plated, ... Chromated, passivated, zinc plating, phosphated, Dacromet,copper plating, gold plating and etc as per your need. Camera Screw salt spray time ...