Semicircular head hexagon screws are precision threaded fasteners with an internal hexagonal drive, also known as Allen hex drive. Made of grade 10.9 alloy steel, strong and durable, corrosion-resistant property, good wear resistance, high hardness and high strength, can be used in extreme environments. - Material: grade 10.9 alloy steel - Thread diameter: 6 mm - Pitch size: 1.0 mm - Color: black oxide finish - Shipping content: M6 x 40 mm (20 units) + M6 nuts (20 units) - Perfect for mechanical engineering, electronics, automotive and more applications