The Nicholson adjustable flexible file holder is size number 25 to hold 12" or 14" long flexible files for secure grip and maintain a curve while filing. A screw thimble provides adjustment for file size and can set the file"s degree of outward or inward curve. The file holder is made of steel for strength.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 are 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 finish than equivalent American pattern files. For Swiss pattern files the length of the tool is the length of the blade, not counting the tang, which is the pointed end fitted for a handle; for American pattern files the length of the tool is its entire length, including the tang.Nicholson manufactures hand tools and power tool accessories. The company is headquartered in Sparks, MD.