3M™ Hookit™ Purple Abrasive Discs are designed for fine featheredging, the last final sanding step before priming, or prepping before blending. These discs feature high-performance sheets designed to cut fast and last long, enabling the user to obtain maximum usage from each disc. They are excellent for use on tough marine gel coat, paint and primer systems. Use with the suggested 3M™ Back Up Pad 05551 and 05775.