A traditional nut used for all bolting and fastening applications. Zinc plated for internal use. Plated in Trivalent Chromium (Cr3) Zinc Standard metric thread" Thread Dia. mm: M20 Socket Size mm: 30 Height mm: 16.0 Thread Type: Metric Finish: Zinc & Clear Cr3 Material: Carbon Steel Timco Hex Full Nuts - Zinc (Size M20 - 20 Pieces) in Silver