I needed to deburr sheet metal but had trouble with the standard deburring tool. After struggling with a standard tool, I asked the sheet metal workers at my job what they use, and here it is. Circular knives are adjustable for different thicknesses and the knives can be twisted or turned for longer life. The design is such that the top and bottom edges of the sheet metal are stripped simultaneously. The guard protects your fingers from sharp burrs, while the handle provides a secure grip. Very quick and easy to use.