Innovative, patented hand abrasive blocks Works 4 times faster than sandpaper or sanding sponges Great for wood, metal and drywall Can be used on any surface Produces a continuous self sharpening abrasive surface as it wears thats guaranteed not to clog, tear or dull Non toxic, chemical free Can be trimmed into smaller sizes for curved or tight areas Use wet or dry Stands up to water and solvents Removes rust from metal