For extending the length of threaded bar. Plated in Trivalent Chromium (Cr3) Zinc Standard metric thread" Thread Dia. mm: M6 Socket Size mm: 10 Height mm: 18.0 Thread Type: Metric Finish: Zinc & Clear Cr3 Material: Carbon Steel Timco Hex Connector Nuts - Zinc (Size M6 - 200 Pieces) in Silver