Lay the end of a piece of wire that requires straightening on the three rollers, then move the rollers until they form a triangle with the wire in the center. Grasp the rollers in one hand holding tightly, then pull the wire through the rollers to straighten. May need to pull through a second time for highly bent wires. Nylon rollers help keep Artistic Wire coating intact. Measures 1.5" x 1.75"