The Nicholson thread-restoring hand file is 8-3/8" long, has a square shape, and has thread teeth to restore damaged extra-fine to extra-coarse external threads on bolts. The file has teeth on both ends to fit the following thread sizes: 9, 10, 12, 16, 20, 27, 28, and 32 threads per inch (TPI). It has no teeth in the center to allow for grip.Hand files are used to remove material and smooth and shape workpieces. They have forward-facing cutting teeth and cut when pushed over either a stationary or rotating workpiece. Single-cut teeth have single rows cut diagonally across the width of the file. Double-cut teeth have two sets of rows cut in opposite directions. American pattern files have three coarseness grades. Coarse, also known as bastard cut, is suitable for efficient, heavy material removal where finish is not a concern. Medium, also known as second cut, offers average material removal and finish quality. Fine, also known as smooth cut, provides the smoothest finish. Swiss pattern files have eight coarseness grades, from 00 (coarse), 0 (medium), and 1 to 6 (fine to finest), offering a smoother, more precise finish than equivalent American pattern files.Nicholson manufactures hand tools and power tool accessories. The company is headquartered in Sparks, MD.