Weiler 1-1/8" Knot Wire End Brush features a hollow end, heavy-duty brushing action with some flexibility for more demanding cleaning and deburring applications in recessed areas on steel, armored steel, cast iron, ductile iron and tool steel parts. 1/4" stem diameter for use on CNC/milling/automatic machine, die grinder, drill, drill press, right angle die grinder and straight grinder.