Our 3Mâ„¢ Cubitronâ„¢ II Hookitâ„¢ File Sheets 737U combines the highest 3M technology for automotive repair. Its long-lasting triangular shaped grains make the sheet ideal for paint stripping, rough shaping of body filler and sanding plastic filler. Our Hookitâ„¢ system makes for quick change-outs of abrasive sheets.