This is a 12 inch sharpening steel with round steel and a black handle, which has been designed for commercial kitchen knives. Simply hold your knife at a 20° angle and you will be able to quickly hone it.
While these items are called a "sharpening steel" — these items technically speaking "hone" your knife. This means its designed for knife maintenance: it will keep a blade extremely sharp, but eventually that knife will also need to be sharpened on a sharpening stone or some other sharpening device. These items keep the edge sharper longer by "realigning" the blade and removing nicks, so it's a perfect tool for maintaining your knives' sharpness.