A common myth is that sharpening steels actually sharpen knives, and can replace stones or other sharpening devices. Steels actually hone a knife and help keep its edge if used regularly. A steel should be used before and after each knife use for proper maintenance. Easily enough, it's used the same way you use a sharpening stone. To find the proper angle, hold the knife horizontally with the edge touching the steel. Move the spine upward to create a 45-degree angle, and then half that again for your optimal sharpening angle.
When attempting to choose a whetstone for sharpening your favorite knife, the number of choices can be mind boggling. In fact, sharpening stones are divided into four distinct categories consisting of natural whetstones and manufactured whetstones which, in turn, are divided into two other categories consisting of oil stones and water stones. Then, there are numerous different varieties of natural whetstones consisting of several different materials that are quarried from different places around the world as well as several different types of man-made whetstones!
Besides ceramic steels, there are also grinding steel that have a layer of diamond. The hard diamond grains ensure that you can quickly regrind your knives. Compared to a ceramic steel, the result slightly less refined. A disadvantage of a diamond steel is that over time the diamond grains may break out or crumble off, which causes the steel to lose it's sharpening quality.
However, it should also be noted that “water stones” are generally significantly softer than oil stones and thus, water stones generally cut faster than oil stones but, they also have to be flattened more often that oil stones do. Furthermore, it should be noted that some water stones must be soaked in water for several hours prior to use whereas, others are of the “splash and sharpen” variety and thus, they only need to be soaked for a few minutes before use and then wetted down occasionally during sharpening process. Diamond hones on the other hand are more durable than either water stones or oil stones and, because they generally have a more coarse grit, they cut faster than natural whetstones. Plus, due to their construction, they never need truing and, in fact, coarse diamond hones are often used to flatten both natural and synthetic whetstones.
This tiny, retractable rod has actually been designed for light sharpening and honing all in one step. Based on its size, I believe that this rod is best used by those who are uncomfortable flinging long knives and rods around as they attempt to put a finer edge on their blades. Its compact nature also makes it perfect for those who need to bring it with them on the go.