The Fällkniven DC4 is a pact double-sided ening stone. One side is made from cerics for that fine finish. The other side is a diond-coated ening stone (25 micron) to preen your knife. bined the DC4 is the stone to keep close in your bapa to make sure you never have to use blunt knives. Fällkniven DC4: en even the hardest types of steel on the road. The ceric stone is made from synthetic sapphire. The of this material is that it,in time,it won't lose its flat surface. This also applies to the diond-coated side. In addit,with these hard materials you can even en knives made from extremely hard powder types of steel. The stone does not any water or oil during use. You only ocnally need to clean it with warm water and liquid soap. The stone might feel a little rough at first,but will bee smoother during use. The leather sheath has a smooth front and a rough ba. You can use the ba as a strop..