Unmounted 1/8" Arbor Hole Brushes - 5/8" Brush Diameter 30% additional fill gives more body for the right feel and longer brush life. Metal hubs with thinner profiles are assembled on specially designed production equipment. The result is a perfect brush. Bristles won't split and washers won't spin. Sold by the dozen. Available in 3 degrees of bristle stiffness: soft, medium or stiff.