When you need to get it sharp, the 204 is all you need. Spyderco's Tri-Angle Sharpmarker includes two sets of high alumina ceramic stones. There is a pair of medium grit (brown) for aggressive sharpening and a pair of fine (white) for professional grade finishing. Also included are a set of brass safety rods to protect the user's hand during sharpening. For sharpening plain edges, the flat sides of the stones are ideal. For serrated edges use the corners. The stones fit into keyed holes and slots molded into the polymer base and have a 40 degree and 30 degree sharpening angle for knives and 12.5 degress scissor setting. Each stone has a groove running its length for sharpening pointed objects like darts, awls and fishhooks. Everything packs neatly into the base and the lid snaps shut making the 204 self-contained and small enough to take with you. No oil, water or lubricants are required during use for dry, mess-free sharpening. Includes instruction book and video.