The 3M™ Trizact™ Hookit™ 443SA disc is used to remove and refine scratches from sanding before using the 3M™ Perfect - it™ polishing system. Use the 3M™ Trizact™ Hookit™ 443SA disc to remove scratches from sanding before repairing car panels using the 3M™ Perfect - it™ polishing system. Our foam disc reduces scratches on the grinding paint before polishing.