Use in either an electric or pneumatic drill. Leaves a clean hole that requires very little grinding . Self centering point minimizes walking, will not require a punch. Solid one piece construction will not break or snap. Made in the U.S.A. This set of 4 spot weld cutters operate up to 2000 RPM. Leaves a clean hole that requires little grinding. It's self centering and doesn't require a punch. These are a solid one piece constructed cutter and are made durable! The set includes the following sizes: 1/4", 5/16", 3/8" and 1/2".