Dewalt accessories DW4902 1″ knot wire end brush is made up of highly specified wire grades that are constructed with internal holding plate to ensure consistency and safety, even balance which provides smooth performance, wire is 100% inspected to meet demanding quality specifications, 1/4″ stem arbor size, maximum speed is 20,000 rpm, knotted wire is for heavy material removal, crimped wire provides flexibility for light removal of rust and paint, general cleaning.