Sharp hooks are critical for angling success, and regardless of what you are told, all hooks will need sharpening from time to time. Our two-sided hook files feature dual sharpening grooves for honing hook bottom and point as well as flat areas for side sharpening of points. Hook files are constructed of stainless steel with dual diamond grit surfaces. 4" model has a fine side (600 grit pattern) and medium side (300 grit pattern), while the 6" model has medium (300 grit pattern) and heavy (150 grit pattern).