SIZE: #8 x 1-1/2" Specification: Screw Diameter: #8 (4.2mm) Screw Length : 1.5?(38mm) Material: 410 Stainless Steel ( Tensile- 180,000 PSI, Hardness- 40 Rockwell C) Thread Type: UN Thread Style: Right Hand Installation Type: Screw In Color: Silver Tone Package Included: 100 PCS Hex washer head self drilling screws are designed with a drill point at the tip to pre-drill the screw hole as you go with a ?thrilling-like? action (threading or drilling) to eliminate separate drilling, tapping, and installation actions. The length of the drill determines the material thickness which the screw can reliably penetrate. They are ideal use for wood, metal or other tough materials and known for their effecient application performance and endurance. You could see them around because they are widely used in a variety of industries such as construction, manufacturing, engineering, assembling and so on. The high quality 410 stainless steel provide perfect strength and good corrosion resistance in bad environments like high temperature, cold weather and high humidity areas without the need for time consuming and costly maintenance. Contact Us: If you have any questions when using, please feel free to contact us by Amazon message.