Sharpening kit gives you the ability to sharpen your own reels. We recomend you do this at the beginning of each season. For most of our customers, this will be sufficient for the season. For those who cut a larger size lawn, it may be necessary to sharpen reels oftener. Sharp mowers cut better, sharpen as needed. Sharpenening Kit includes: 1 reel chuck, 1 jar of grinding compound and application brush, 1 instructional video and written instructions. The sharpening process is simple and beneficial.