These Machine Screw Hex Nuts by Prime-Line Products are constructed of stainless steel and come in a corrosion-resistant satin finish. Hex nuts are the most widely used nuts and will work on a variety of applications. They are standard thickness and can be installed with a wrench or socket set. Machine screw nuts, is a subset of finished hex nuts designed for use with machine screws, which are typically much smaller than bolts. These nuts are easy to fasten with socket, closed and open wrenches.