Manual Sure Sharp, An Easy Way To Manually Sharpen A Chain Saw, Provides Accurate Cutter Sharpening, Complete With Built-In Handle and Easy Instructions, File Not Included.With the P308 Sure Sharp chain saw file you can manually file and sharpen your chain. An accurately filed saw chain can help reduce your fatigue. Dial the angle, depth, and file height settings; once set, the file angle and depth settings lock, keeping your sharpening consistent as you work. Complete instructions are included, which is good, because some complex assembly is required.