Detailed Product Description Spring nut, available in different sizes.Metric size:from M6 to M18,with spring or without spring. Inch size: from 1/4 inch to 7/8 inch .with spring or without spring. Materials: low carbon, middle carbon, stainless(A2,A4,304and 316). Surface:zinc plated(Cr6/Cr3), yellow zinc plated,black zinc plated,nickel plated and hot dip galvanization.