Material: Steel Stainless steel 2:Thread size:M2.5,M3,M4,M5,M6,M8 3:Surface :nickel,blue zinc; 1:PEM PSM nut S-M3-1,S-M6-1;2:Material:steel,stainless steel;3:surface :blue zinc,nickle,plain;4:thread size :M3 TO m8mm; PEM nut and standoff/snap rivet/clinch rivet nut fasteners/rivets