The head of the wooly when dipped into the cleaner bucket absorbs the cleaner and allows for even distribution of cleaner covering all of the wheel surface. The absorbent wooly conforms to the wheel allowing it to reach everywhere. The Caliper Woolie is 18" inch long and has a 1.875 inch diameter wool head to reach behind the wheel face to clean the inside area of wheels. This unique angled woolly allows detailers to reach areas that can not be cleaned with traditional wheel brushes. The Wheel Woolies are constructed of soft synthetic wool mounted on long handles. They’re safe on any wheel finish and the wool compresses to fit into tight spaces. Wheel Woolies keep your hands clear of the wheel while you’re cleaning.