Check the listing for details. Spyderco Knives Webfoot Knife & Tool Sharpener 308CBN Cubic Boron Nitride. Color: Gray, Condition: New, Made in China. Listed at 66.75 USD. Made in China, this Webfoot Knife & Tool Sharpener is made of Cubic Boron Nitride and Solid Carbon Steel. This Spyderco Knives SPYDERCO 308CBN SHARP , SY308CBN SHARPNER Webfoot Knife & Tool Sharpener is 7''L X 3''W X 1/4''H inches. The Webfoot is a uniquely different approach to sharpening that can be used anywhere, set up in seconds, and doesn’t require oil, water, electricity, or any complicated clamps or fixtures. It is made of a single piece of carbon steel and coated in Cubic Boron Nitride (CBN)—a state-of-the-art superabrasive that is second in hardness only to diamond. Resting the wide end of the Webfoot on a flat surface and rocking it from side to side aligns its outer edges at the perfect 40-degree included angle for utility knife edges. Simply keep the plane of your blade vertical and draw it from heel to tip.