I'm an Eagle Scout, and I know how to sharpen a knife. I work as a cook, and cooks also know how to sharpen and use knives.Or at least I thought I did. That is until I got my Wicked Edge sharpener.O.M.G. are the knives that can come off this device sharp. I actually frightened the chef where I worked. He was almost scared to use the knife I loaned him.You can actually feel the edge of a large chef's knife sink into wood cutting boards as you use them. I can slice tomatoes, ripe tomatoes, with non-serrated knives using just the weight of the blade. I am not joking, this thing makes sharper than factory edges.The key to this device is the word 'precision'. With this device, everything locks into place, and you get exactly the same stroke angle with every stroke. All you have to do is maintain roughly even pressure on the strokes you make, and do the same number of strokes on each side, which is dirt simple.It comes with stones from 100 to 600 grit. Chef knives should generally be sharpened to around 800 grit in my experience. So, to do this, you will want to buy the next finer grit stone, which adds 800 and 1000 grit. Finer grits are great for paring knives, and some other blades, but anything finer than 800 is too fine for a large or medium chef's knife. You can stop at 400 or 600 grit for a knife you want to use for slicing only.Not only is this sharpener capable of scary sharp knives, it is fast. It takes about 10 minutes the first time you use it on a chef knife, and about 1/3 of that for periodic sharpening after that.The one downside, beside the price, it that you really need to buy the fine angle attachment to sharpen most pen knives, and IMO, it's WAY over-priced.I suggest you watch some YouTube videos by the owner before using it, to do so correctly, quickly, and safely.BTW, I did not buy a base for mine. I found a round edge-glued wooden disk (Like the top of a bar stool) at Home Depot (12" diameter, on-line, not carried in stores) for about $10, sanded and coated it with 2 coats of polyurethane, then mounted the Wicked Edge to it. I also bought a pack of rubber feet and put 6 large ones on the bottom so it won't slide around. Works great, and 1/3 the price of the Wicked Edge base. The device DOES need to be mounted to something.I made a sheet of paper and list each knife on it as I sharpen it, listing the finest grit and position in the vice, so I can maintain exactly the same angle every sharpening.Seriously, if you want a sharp blade, this is the sharpener to buy. I own a couple of other sharpeners, some inexpensive, some pretty pricey, but this is, without question, the best sharpener I have ever owned or used. My highest recommendation.