3M 31363 3" 150 Grit Cubitron II Clean Sanding Hookit sandpaper Discs Box of 50. Our Cubitron™ II Hookit™ Clean Sanding Abrasive Disc 737U combines the highest 3M technology for automotive repair. Its long-lasting triangular shaped grain and multi-hole pattern for superior dust extraction make the disc ideal for paint removal.