The DC3 and DC4 are a combination diamond/ceramic whetstone that will handle all your sharpening needs. The newly-developed DC3 and DC4 whetstones consist of a fine diamond stone (25 micron) and a very special ceramic stone, made of synthetic sapphire.
The advantage of these materials is that, over long periods of use, they will keep their flat shape which is important when sharpening your knife. And, since these materials are ultra sharp they will sharpen any steel, even the extremely hard powder steels.
You do not need to lubricate these stones, but now and then you should consider cleaning them with warm water and liquid soap. The stones might feel coarse from the start but will become smoother after some use. A leather pouch is included.