Bore Polisher Abrasive Type Coated Grit 120 Abrasive Material Aluminum Oxide Series R369 Backing Material Cotton/Polyester Backing Weight Y Compatible Bore Inner Diameter (Maximum) 4 in Compatible Bore Inner Diameter (Minimum) 3 1/8 in Maximum Operating Speed 10 000 RPM Compatible Mandrel Grainger Part Number 3RB57 464P95 Compatible Mandrel Manufacturer Model Number 08834154183 08834154187 08834154461