Robtec 4 in. Stem-Mounted Knot Wire Wheel provides a medium-duty brushing action with some flexibility for demanding deburring applications on steel. The permanently-attached 1/4 in. stem is intended for use on CNC/milling/automatic machines, die grinders, drills, drill presses, right angle die grinders and straight grinders. The wheel has 18 twisted knot strands.