This SIQUK package includes 130 50mm sanding discs with 1pc 1/4" Shank Backing Pad and 1pc Soft Foam Buffering Pad. Each grit comes in 10 pieces: 60/ 80/ 120/ 180/ 240/ 400/ 600/ 800/ 1000/ 1200/ 1500/ 2000/ 3000, for a total of 130 pieces. These sanding discs are made of aluminum oxide, an abrasive, durable, and anti-static material, which is useful for cleaning and polishing corners in metal, wood, jade, and other materials. The kit also includes a soft foam pad to reduce vibration during use. These sanding discs have a 50mm diameter hook and loop backing, making them suitable for most rotary tools, such as grinders, air grinders, and electric drills. Please note that these sanding disc pads combine with a 2-inch backing pad and are not suitable for adhesive sanding pad. Before using them, be sure to clean the dust and replace the old sanding pad. The use of goggles or eye protection tools is recommended during use.