Wood Hub Wheel Brush, 1 Row, Upright, Overall diameter 3" Wood Hub Wheel Brush, 1 Row, Upright, Overall diameter 3" consists of Chungking bristles mounted into a hardwood hub with 1/4" arbor holes to fit tapered spindles of polishing motors. Wooden Hub diameter is 1 1/4", Trim length is 7/8". Bristle tufts are "staple-set" into wood hubs to remain securely fastened.