3" (76.2mm) diameter x 1" (25.4mm) wide x 1/4" (6.35mm) shank. High Performance Aluminum Oxide provides durability, heat resistance, moisture resistance, anti-clogging, and anti-static. Max RPM 20,000. Quickly shape, sand, and grind with these 2 Premium sanding discs. Includes 2 Premium 60 grit Flap Wheel Sanding Discs.