M3 x 0.50 Coarse Thread DIN 985 Class 8 Nyloc (Nylon Insert Locknut) Standard Medium Carbon Steel Black Oxide Pk 2500: Amazon.com: Industrial & Scientific
M3 x 0.50 Coarse Thread DIN 985 Class 8 Nyloc (Nylon Insert Locknut) Standard Medium Carbon Steel Zinc Plated Pk 100: Amazon.com: Industrial & Scientific