NO BLADE DAMAGE: This tool will sharpen the blade of your knife effortlessly without wearing the blade like a grinder. You dont have to plug it in and no batteries are required. Just draw your knife back and forth restoring the blade to its super sharp state, as good as new. EASY TO USE ON PLAIN EDGED AND SERRATED BLADES: It gives you the perfect angle to sharpen both sides of a straight or serrated blade, leaving you with a super sharp knife. It takes out the difficulty of using a butcher's steel. SPRING HONING TECHNOLOGY FOR EASY ACTION: The patented technology reproduces the action of a butcher's steel, automatically ensuring the correct edge angle is applied equally to both sides of the blade. The mechanism uses two spring loaded butchers steels, revolving under tension without wearing the blade. This has to be the best Knife sharpener ever!! The mechanism (Royal designer for industry, Robert Welch) is on permanent display at the New York museum of modern art. LIFETIME GUARANTEE: This product carries a lifetime guarantee against defects in materials and workmanship under normal kitchen use. Made in Sheffield United Kingdom. DEVELOPED FOR, AND STILL USED IN THE MEAT PROCESSING INDUSTRY: This revolutionary product was originally designed for the professional meat processing industry, where knifes are seriously put through the rigors of commercial use.