CENTURY'S POLISHING BONNETS ARE MADE OF EXTRA THICK LAMBS WOOL BLEND DRAW STRING. POLISHING BONNETS FIT FLEXIBLE BACKING PADS FOR USE ON ELECTRIC DRILLS. EXTRA THICK LAMBS WOOD BLEND DRAW STRING POLISHING BONNETS FIT FLEXIBLE BACKING PADS FOR USE ON ELECTRIC DRILLS. FITS POPULAR POLISHING EQUIPMENT.