The Forney 72784 4-Inch Twist Knot Wire Wheel Brush provides high-impact. These wheels are used in surface preparation prior to welding and for removing weld scale, spatter and heavy corrosion. Used for heavy duty cleaning applications. Forney Industries is one of America's longest operating family-owned metal working product companies. Founded in 1932, Forney offers more than 5,000 products for the hardware, automotive, farm and ranch and do-it-yourself markets. 4-Inch (101.6-mm) by0.020-Inch (0.305-mm) with M10 by 1.25 arbor. Max 20,000-RPM. Claims for warranty must be made within 90 days of the date of purchase. Proof of purchase required. This warranty does not cover any product that has been subject to misuse, neglect, negligence or accident, or that has been used in any way contrary to the purpose intended.