Firm backing pad with semi-flexible edge and 8 holes for dust extraction. For use with hook and loop polishing sponges, bonnets and sanding discs. Compatible with air sander polishers. 5/16″ UNF male thread. Max 10,000rpm. Firm backing pad with semi-flexible edge and 8 holes for dust extraction. For use with hook and loop polishing sponges, bonnets and sanding discs. Compatible with air sander polishers. 5/16″ UNF male thread. Max 10,000rpm.