Features: Aluminium Oxide corundum abrasive grain has high abrasion resistance and hardness, and the surface is attached with thermal and blocking resistant coating, which can improve the grinding efficiency and service life. Suitable For:carbon steel, cast iron, titanium, aluminum, brass, bronze, copper or hard woods and can also be used on stainless steel, cobalt alloys and nickel alloys. Specification: Material: Aluminium Oxide Color: red Size: 1 inch Grit: 240 Grit Type: Quick Change Speed: 25,000 RPM Quantity: 100Pcs Package Content: 100pcs Aluminum Oxide sanding discsNote: The colors brown and red are random and will vary from batch to batch.