Because the brush is facing the side, it is possible to polish only the crossing hole in a blind hole.Ideal for removing burrs on crossing holes.Working tool: electric drill, drill press, etc.Wire Diameter (mm):0.3Bristle Material:Steel WireOuter Diameter x Bristle Thickness x Shaft Length x Shaft Diameter (mm):20 x 10 x 25 x 6Max Working Rotation Speed (rpm):3000Shaft: SteelAir tools cannot be used.