• The MT-1 Countersunk Screw was developed when Red Rock Rifleworks discovered there was no set of commercially available fasteners to achieve a flush surface when fastening two sheets of 1/8 inch Kydex® together. The countersunk screws are composed of 18-8 stainless steel and have a special undercut profile. Only 1/4 inches in length their tensile strength (70 ksi) is a good match to the tensile strength of the aluminum alloy nut (99 ksi). Like the nuts, the screws are black in color (black oxide process) to match the MT-1 Sheath.