Rotate these dies around studs and rods to create new fastener threads. A cut above lower-quality dies that can leave inferior threads, these are machined in the U.S. to precise dimensions for accuracy and consistency.
They are adjustable, so you can cut a shallow thread that makes it easier to get the die started on the first pass. Turn the set screw to open the die to its largest diameter. Then rotate the die with a round die wrench and adjust the screw as you make additional passes to reach the proper thread size.