Product Name: Hex Socket Button Head Bolts; Material: Alloy Steel; Surface Treatment: Blackening; Performance Grade: 12.9; Color: Black; Dimension: M3 x 16mm; Rod Length(Under Head): 16mm / 0.63"; Pitch: 0.5mm / 0.02"||Inner Hex Width: 2mm / 0.08"; Screw Head Size: 5.5 x 1.5mm / 0.22" x 0.06"(Dia.*Thickness); Package Content: 100pcs x Hex Socket Bolts||Feature: Button head machine screws, hex socket drive. Metric machine screws for universal use.||Material: Made of alloy steel, black oxide coating finish, wear-resistant, anti-corrosion, and it is smoother to use.||Application: Widely used where fastening is required, the assembly and maintenance of households, machine tools, construction, and DIY projects. Such as household hardware, electrical products, mechanical equipment products, etc.