The SpitJack 12 inch steel sharpening rod is an essential tool for keeping your knives sharp. Over time and continued use, the original factory sharpening of the blade wears down. If the steel used to make the knife is of good quality, and if the knife hasn't had too much normal use and is not damaged, it is possible to "turn" the edge back to sharpness by using a steel (such as this product) or ceramic hone. Using the proper techniques, in just a few seconds you can restore your blade to sharpness. This can be done every time you use your knife to maintain optimal sharpness. Eventually, your blade edge will be deformed (even with proper maintenance with a sharpening steel) to the point where a new edge has to be created. Note: this requires different tools and techniques and cannot be done effectively with this product. The SpitJack sharpening steel is a full 12 inches long to allow you to properly and easily sharpen 12 inch long knives of any type - even serrated blades!