Stainless Steel Metric Serrated Hex Flange Lock Nuts (DIN 6923). These have a A2-70 / 18-8 Grade rating and are all in standard metric coarse thread.

Available Sizes :

M3 (3mm x 0.50), M4 (4mm x 0.70), M5 (5mm x 0.80),

M6 (6mm x 1.0), M8 (8mm x 1.25),