The 8G4033.5X4.0B part of Dremec is an 8-inch, 40-grit, sanding disc with a 4-inch diamter. It is designed to fit onto 4-inch disc sanders or 3-inch orbital sanders to provide a fast, effective removal of material, helping you to finish jobs quickly with a smooth, professional-looking finish. It is silicon carbide-coated to offer a long-lasting and durable abrasive surface, ideal for wood, soft metals and painted surfaces. The discs are also anti-clog and load-resistant, preventing material build up so you can work efficiently and effectively.