The McMaster-Carr 6324K13 is a stainless steel hex drive flat head screw with a thread diameter of 1/4"-20. It has a head height of 3/16" and a head diameter of 5/16". The screw has a tensile strength of 85,000 psi and meets ASME B18.3 standards. The screw is made from 18-8 stainless steel for corrosion resistance. It can be purchased in lengths ranging from 1/4" to 3" and comes with a hex drive for use with hex wrenches or hex drive bits. The screws are ideal for applications requiring corrosion resistance like marine environments.