The ceramic cone is an ideal sharpener for those not comfortable using a flat stone. The ceramic cone is very easy to use as the angle is built in. All you do is keep the knife vertical and draw it down and back. You use it dry and it is a quick and efficient way to sharpen your knife. Ceramic is a great material to sharpen on as it has the hardness of glass (harder than steel) and will not wear away. Use this cone dry. It is 180mm in length.