3M Hookit™ 9" Diameter Double-Sided Wool Compounding Pad. Built to deliver an aggressive cut for a smooth finish, ideal when compounding on paints, clears and composite surfaces. Double-sided screw-on pads feature 100 percent untwisted wool yarn on a stiff central hub for a full cut and broader surface contact. Single-sided pads feature a finer 60/40 wool blend and 3M Hookit™ attachment for quick change-outs.