Shutter Grinding Discs 10 Pack 4.5 Inch 40# Sanding Discs High Density Aluminum Oxide Abrasive Grinding Wheel Grinding Discs For Metal And Wood Grinding Product parameters: The louver disc is made of high-quality alumina resin fiber and glass fiber backboard, with high density and wear resistance. 10 40# grain size grinding discs, with an outer diameter of 4.5 inches and a mandrel of 0.87 inches. Great Compatibility: Our flat discs can work with most air and electric sanders as well as angle grinders up to a speed of 18000 RPM. The fiberglass backboard can effectively absorb the vibration during use, bringing you a stable and efficient grinding experience. Grinding Specialists: These louvered discs are designed for grinding, deburring, cleaning, chamfering, sanding and finishing on a variety of surfaces. It is suitable for rust removal and paint removal, and has excellent welding performance. Ease of use: While our products are professional, users cannot be experts. This professional louver disc offers excellent wear resistance and fast polishing to provide maximum surface contact on smooth or curved surfaces. Not only for professional workers, but also for recruiting. Safety Tip: Wear goggles and gloves before starting work. Watch out for sparks, don't launch them at flammable objects and other people. No need to press too hard to save your labor, it still works fine.