Feature: 1. Made of pure copper material, not easy to corrode, not easy to be damp and not easy to oxidize. 2. The thread is deep and neat and clear, and the force is even and not easy to slip. 3. The surface is flat and smoothly without burrs, with great workmanship and has a long service life. 4. There are multiple specifications of M3, M4, M5, M6 to choose from. 5. With 50pcs nuts, can meet your use and replacement needs, very practically. Specification: Item Type: SelfLocking NutMaterial: Pure copper Specification Pitch e s h m M3(approx.) 0.5mm 0.02in 6.2mm 0.2in 5.5mm 0.2in 3.55mm 0.1in 2.6mm 0.1in M4(approx.) 0.7mm 0.03in 7.8mm 0.3in 7.0mm 0.3in 4.4mm 0.2in 3.4mm 0.1in M5(approx.) 0.8mm 0.03in 9.05mm 0.4in 8.0mm 0.3in 5.0mm 0.2in 4.0mm 0.2in M6(approx.) 1.0mm 0.04in 11.45mm 0.5in 10mm 0.4in 6.25mm 0.2in 5.2mm 0.2in . Package List: 50 x SelfLocking NutMade of pure copper material, not easy to corrode, not easy to be damp and not easy to oxidize. The thread is deep and neat and clear, and the force is even and not easy to slip. The surface is flat and smoothly without burrs, with great workmanship and has a long service life. There are multiple specifications of M3, M4, M5, M6 to choose from. With 50pcs nuts, can meet your use and replacement needs, very practically.