The Tri-Angle Sharpmaker from Spyderco is a grinding tool that has been on the American market for a long time.
Insert the rods into the holes shown in the illustration, then hold the knife vertically and pull it down towards you. Use the entire surface to sharpen your knife.
A very good alternative for you who have a little difficulty keeping the angles of a sharpening steel.
Choose between a 15 or 20 degree angle per side.
15 degrees for example for Japanese knives.
20 degrees, for example for European knives.
2 pcs medium and 2 pcs fine ceramic rods are included (buy extra diamond rods if needed below).
An instructional DVD is included, but can also be viewed on Youtube.