When you need to get it sharp, the 204 is all you need. Spyderco's Tri-Angle SharpMaker includes two sets of high Alumina Ceramic* stones: A pair of medium grit (dark) stones for aggressive sharpening, and a pair of fine stones (white) for professional grade finishing. There is also 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 a 12 1/2 degree scissor setting. A groove running the length of the stone is for sharpening pointed objects like darts, awls and fishhooks. All components pack into the base and the lid snaps shut making the 204 self contained and small enough to carry in the field. No lubrication is required during use for dry, mess-free sharpening. Includes a great instruction video and booklet.
Made in the U.S., Alumina Ceramic is a ceramic compound formed when alumina particles (synthetic sapphires) are mixed with a ceramic bonding agent. The mixture is shaped, then kiln fired at temperatures in excess of 3000 degrees Fahrenheit for up to three days. Alumina ceramics come in three grits: Ultra fine grit, fine grit (both are closed celled and never wear over time or use), and medium grit (open cell which does wear out over time). The Tri-Angle Sharpmaker includes a pair of the fine grit and the medium grit stones.
The Tri-Angle Sharpmaker is my favorite sharpener. In fact, I keep one set up on my desk for keeping my knives in tip-top shape. A special recommendation: If you find yourself sharpening knives or tools that become very dull, I also highly recommend Spyderco's Diamond Hones to fit the Tri-Angle SharpMaker. Jeff