Made from high grade collet steel and precision ground to exacting tolerances. Sizes include: 1/8-Inch, 3/16-Inch, 1/4-Inch, 5/16-Inch, 3/8-Inch, 7/16-Inch, 1/2-Inch, 9/16-Inch, 5/8-Inch, 11/16-Inch, 3/4-Inch, 13/16-Inch, 7/8-Inch, 15/16-Inch and 1-Inch.