Loose-leaf construction with 40 layers of cotton. For polishing and finishing; open structure reduces heat build up. For best results use one compound per wheel. Can be stacked onto tapered spindles to achieve required thickness. 16mm / 5/8″ bore for use with all 150mm bench grinders and polishers. Loose-leaf construction with 40 layers of cotton. For polishing and finishing; open structure reduces heat build up. For best results use one compound per wheel. Can be stacked onto tapered spindles to achieve required thickness. 16mm / 5/8″ bore for use with all 150mm bench grinders and polishers.