Features: Self-Drilling Screws, also known as Tek screws, eliminate the need for a pre-drilled hole. The length of the drill point determines the material thickness which the screw can reliably penetrate. When selecting a self-drilling screw design, it is important to consider the material thickness and type of materials to be joined. It is wood drill tail screw, mainly used in steel structure Caigang watt fixed can also be used for fixing the simple construction of the sheet material. It can not be used in combination with metal and metal. Teks self-tapping screws provide secure fastening with strong holding power without the need to pre-drill. Specifications: Color: Black for Head Style: Hex Washer Head for Head Diameter: 8mm/0.31" Thread Diameter: 4.8mm/0.19" Thread Length: 19mm/0.75" Total Length: 22mm/0.87" Quantity: 10 Pcs Note: Please allow 1-3mm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you No Retail Package Package Contents: 10 x Self-Tapping Screws