The diamond triangles fit into Spyderco's existing 204MF Tri-Angle SharpMaker system, and enable the system to sharpen most anything. Hollowed out to lessen overall weight, each rod is seven inches long and the three flat (triangular) sides are half an inch wide. Made of nickel-coated steel and plated with microscopic diamond particles, they are moderately coarse at 400 grit and capable of removing a great deal of metal quickly during sharpening. Running the length of each rod is a channel for honing pointed items such as fishhooks, awls and darts. The three corners of the triangle make quick work of re-beveling serrated edged cutlery and the flat sides effortlessly hone PlainEdges. An inch along the bottom of each triangle is not diamond plated allowing the rods to smoothly slide into the SharpMaker's base. Highly recommended for aggressive sharpening, re-beveling and reshaping only. Clean them after use by rubbing off with a dry cloth. Sold as a pair.