Spyderco's Tri-Angle Sharpmaker includes two sets of high Alumina Ceramic 7" stones: medium grit for aggressive sharpening and fine grit for professional-grade finishing. Stones fit into keyed holes and a set of brass safety rods protect the user's hand during sharpening. The triangular shape allows honing of serrated and plain edges. Slots molded into the polymer base have a 40- and 30-degree angle for knives and a 12.5-degree scissor setting. A groove running the length of the stone is for sharpening pointed objects like darts, awls and fishhooks while a channel on the flipside allows for a bench stone-type set up. Includes instruction book and video.