40 pieces of mixed grits: 40 pieces of mouse sandpaper, 40/60/80/120 mesh, 10 pieces of each mesh. Meet your different needs. [Abrasive material]: aluminum oxide, durable, anti-static, a good choice for grinding and polishing; Back: Velcro, easy and quick to apply, strong and durable; 4 pre-drilled holes for dust removal. Instructions for use Please remove dust and replace old Velcro pads before use. [Material] Made of aluminum coating high quality aluminum oxide, anti-static, resistant to grinding, stable and capable of continuous polishing work