A pull-through sharpener  Which has guides to pull your knife blade through; you can find Inside it sharpening abrasives to grind away the imperfections of your blades and honing the blades to straighten your bent metals. A whetstone It is a solid block of harder materials than your blade's steel. And pulling your blades across the grit will sharpen it. Both types have sharpening elements of various grit levels.