Flap Disc Abrasive Type Coated Abrasive Material Zirconia Alumina Grade Medium Backing Plate Material Plastic Connector Size Not Applicable Connector Type Threaded Hole Density Rating High Flap Disc Type Type 27 Overall Diameter 3 in Quick Change System TR Series SPINLOCK Backing Material No backing Material Backing Weight Not Applicable Coating Coverage Not Applicable Grit 60 Maximum Operating Speed 20 000 RPM Color Dark Grey