Crescent® Nicholson 8" x 1/4" High Carbon Steel Round Chain Saw File is a professional-grade file that is designed for sharpening chainsaw blades. It is made from high-carbon steel for durability and features a knurl-cut design for fast and efficient sharpening. The file is 8" long and has a 1/4" diameter. Straight tang. File from inside to outside of cutter. Place file against beveled cutting surface of teeth 20 degree to 45 degree with saw. Sharpen all left hand cutters on one side of chain then move to the other side and file all the right hand cutters. Height between cutting teeth and depth gauge is between 0.020 to 0.030 inch.