21 Piece Cobalt High Speed Steel Drill Bit Set includes 1/16-Inch, 5/64-Inch, 3/32-Inch, 7/64-Inch, 1/8-Inch, 9/64-Inch, 5/32-Inch, 11/64-Inch, 3/16-Inch, 13/64-Inch, 7/32-Inch, 15/64-Inch, 1/4-Inch, 17/64-Inch, 9/32-Inch, 19/64-Inch, 5/16-Inch, 21/64-Inch, 11/32-Inch, 23/64-Inch and 3/8-Inch. No center punch needed: Century 135 degree Quick Cut Points are self-centering and penetrate faster with less pressure. Will not walk or wander at the starting surface. Extremely heat resistant, must be used and operated in power units that have a RPM speed of 1500 or more for maximum efficiency. 12 times life rating.