A wider outer diameter than a Form A & B. Used to increase the clamping area. Plated in Trivalent Chromium (Cr3) Zinc"Hole Dia. mm - M20Outer Dia. mm - N/AThickness mm - 4.0Finish - Zinc & Clear Cr3Material - Carbon Steel Timco Form C Washers - Zinc (Size M20 - 100 Pieces) in Clear Size: 1000mm x 1000mm