Feature: 1. Great workmanship, with smoothly surface without burrs, strong and durable. 2. The surface is glossy and deep, the screw teeth are sharping, the force is even, and the rotation process is not easy to slip. 3. Made of 304 stainless steel material, corrosion?resistant and rust?resistant. 4. With 350pcs, can meet your use and replacement needs, very practically. 5. Strict quality control and quality assurance, high safety factor, can be used with peace of mind. Specification: Item Type: Concave End Tightening SetMaterial: 304 stainless steel Model and Quantity:50 x M3 x 3 Concave End Tightening 50 x M3 x 4 Concave End Tightening 50 x M3 x 10 Concave End Tightening 40 x M4 x 4 Concave End Tightening 40 x M4 x 6 Concave End Tightening 30 x M5 x 5 Concave End Tightening 30 x M5 x 8 Concave End Tightening 20 x M6 x 6 Concave End Tightening 20 x M6 x 10 Concave End Tightening 20 x M8 x 8 Concave End Tightening . Package List: 50 x M3 x 3 Concave End Tightening50 x M3 x 4 Concave End Tightening50 x M3 x 10 Concave End Tightening40 x M4 x 4 Concave End Tightening40 x M4 x 6 Concave End Tightening30 x M5 x 5 Concave End Tightening30 x M5 x 8 Concave End Tightening20 x M6 x 6 Concave End Tightening20 x M6 x 10 Concave End Tightening20 x M8 x 8 Concave End TighteningGreat workmanship, with smoothly surface without burrs, strong and durable. The surface is glossy and deep, the screw teeth are sharping, the force is even, and the rotation process is not easy to slip. Made of 304 stainless steel material, corrosion?resistant and rust?resistant. With 350pcs, can meet your use and replacement needs, very practically. Strict quality control and quality assurance, high safety factor, can be used with peace of mind.