ALFA 11” three way knife sharpening system. Uses superior bonded stones in medium, coarse, and fine grit sizes. The system uses a constant oil bath to keep the stones under oil during use. Comes with a 16 oz. bottle of sharpening oil and a handy sharpening guide set at 12 & 20 degrees for the sharpening. It is important to be consistent and sharpen your knife at the same angle each time. Your food preparation knives will perform their best when sharpened at a 15 degree angle on each side of the blade.