The OnFloor 20" concrete grinder can smooth and polish concrete surfaces, depending on the tools used. When used with our concrete scarifier attachment, it can also remove most mastics, adhesives, and coatings. It can be used as either a wet, or dry grinder/polisher. The largest advantage to wet grinding, is the lack of airborne particulate matter. Dry polishing has the advantage of having a completely dry surface, as well as easier cleanup and disposal of concrete dust. Make sure to watch all 9 instructional videos before operating your OnFloor concrete refinishing machine!!