Shape, sharpen, and deburr metal with the ABN Hand Deburring File 3-Piece Set. The round file is double cut throughout and tapers for inside round holes or beveled corners. The flat file is double cut on both sides with a single cut on the edges and tapers for heavy-duty applications. The half-round file is double cut on both sides and tapers for curved surfaces and corners. Before using, we recommend applying a small amount of lard or oil on file teeth to make cutting easier and lessen friction, prevent pins forming and sticking in teeth, reduce metal dust buildup, and prevent rust (if using lubrication, working surface must be clean and free of any lard or oil). Warning: This product can expose you to chemicals which is [are] known to the State of California to cause cancer and birth defects or other reproductive harm.