3M 31364 Cubitron II Hookit Clean Sanding Abrasive Discs, 3 in, 180+ grade, 50 Discs. Cubitron II Hookit Clean Sanding Abrasive Discs 737U combines the highest 3M technologies for automotive repair. Its long-lasting sharp triangular shaped grain and multi-hole pattern for superior dust extraction make the disc ideal for paint removal, rough body filler shaping, fine feather-edging or final prep before blending or priming.