This 4" knot wheel stringer bead twist brush is made in the USA and features a 5/8" - 11 arbor hole size, threaded nut mounting type, and 0.020 in wire diameter. The brush diameter is 4 inches and the trim length is 3/4 inch. The abrasive material is steel and the wire type is knotted wire. This unit is perfect for those in need of a high-quality abrasive brush for their  deburring, weld cleaning, slag removal and other metalworking projects. 20,000RPM rated.  MADE IN U.S.A.