3. hex nuts, heavy hex nuts, jam nuts, nylon insert lock nuts, slotted nuts, welded nuts, square nuts Raw material: steel, stainless steel, PVC, NYLON or others required by our clients. From Size #4 to M64(#4 to 2 1/2? Grade: 2, 5, 8, 10 (4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 10.9, 12.9) Surface treatment: plain finish, black, phosphated, nickel plated, zinc plated, hot dip galvanized, dacromat, mechanical galvanized, Cr+3 etc..