20" Mesh Floor Sanding Screens for low-speed floor buffers, floor polishers, and floor maintainers operating at 175-350 RPMs. These 20-Inch screens are available in grits ranging from 60 to 150. The grit or grain on screens is not as aggressive as typical "sandpaper" as the particles on screens are embedded in a mesh screen and result in fewer grain particles per square inch. These screens are used to scuff, abrade, and dull finishes such as polyurethane and will remove bubbles and imperfections in between coats on floors. They must be used with a standard pad driver and a pad under the machine. Please check your current pad driver size or consult your floor buffer's owner's manual to ensure correct ordering. Partial boxes are NOT returnable.