1000pcs) DIN 6923 M4 Hexagon Flange Nuts with Serration A4 Stainless Steel, Ships Free in USA by Aspen Fasteners, ASSP692344: Amazon.com: Industrial & Scientific
DIN 6923 -flange nuts - serrated nut - hex flange nut- China manufacturer
Amazon.com: 10 M12-1.75 Hex Flange Nut, Class 10, Serrated, Black Oxide. DIN 6923 : Industrial & Scientific
(6000 pcs) M6-1.0, DIN 6923, Metric, Hex Flange Nuts, Class 8 Steel, Zinc Plated: Amazon.com: Industrial & Scientific