20pcs) DIN 125 M52 Flat Washers (54mm ID) Type A A2 Stainless Steel, Ships Free in USA by Aspen Fasteners, ASSP01252540: Amazon.com: Industrial & Scientific
Steel Flat Washer, Zinc Plated Finish, DIN 125, Metric, M12 Screw Size, 13 mm ID, 24 mm OD, 2.5 mm Thick (Pack of 50): Amazon.com: Industrial & Scientific