Item: Aluminum Oixde Abrasive Fiber Sanding Disks for Disc Sander Application: Iron, cast iron, mild steel, aluminum, welding rods, non- ... Model No.: VA113 Type: Fiber Discs Diameter: 4'', 5'', 6'', 7'', etc. Grade: 36, 40, 80, 100, 120, etc. Color: Maroon ... , resulting in a more consistent sanded surface and a longer disc life