Tianli  Sanding Drum Kit : Fine sanding and shaping. Used to create grooves, arcs, or smooth out hole edges on flat wooden boards, metal pipes, and plastics. It is a detail sanding tool, not for large-area floor grinding. Primarily suitable for wood, metal, plastic, and fiberglass. Note: Do not use on concrete, ceramic, or stone, as the abrasive paper will wear out instantly on these hard materials.