Wire Size: M4 x 30mm; hex width: 2.5mm/0.1" Made of carbon steel for higher hardness, corrosion and rust resistance. Self-drilling screws drill well into wood, sheet metal and other surfaces.Threading can reduce resistance when tightening and prevent cracking. It also works well for attaching metal hardware to wood because threaded rods provide good hold in wood. Widely used in various industries such as manufacturing, construction, engineering and assembly. Finishing Made of carbon steel for higher hardness, corrosion and rust resistance. Self-tapping screws drill well into wood, sheet metal and other surfaces.Threads can reduce strength when tightening and prevent cracking. It also works well for attaching metal hardware to wood as the threaded rods provide good tenacity. ue in wood. Widely used in various industries such as manufacturing, construction, engineering and assembly. Specification: Material Material: Carbon Steel Surface Treatment: Black Oxide Performance Rating: 8.8 Thread Size: M4 x 30mm Pitch: 1.3mm Hex Width: 2.5mm/0.1" Screw Head Size: 7.5 x 1.9mm /0.3" x 0.07" (D*T) Package includes: 50 self-tapping screws with hexagon socket.