High carbon bevelled knotted steel twisted wire, Medium bristles, For use with grinding machines, Ideal for corners and hard-to-reach places, Diameter: 4" (101.6mm), Thickness: 19/32" (15mm), Wire Thickness: 0.35mm, Anchor Hole Size: M14, Wire Length: 22mm, No. Of Braids: 18, Maximum Speed: 12,500rpm