The cup shape to enables the maximum number of wire filaments to make contact with the working surface. Cup brushes are ideal for use on flat surfaces. These wire cup brushes feature 1/4" hex shanks. The hex shank allows their use with quick-change bit holders. Alternatively, the shank offers a more positive grip when used in a standard 3-jaw drill chuck Available either crimped or as a twist knot steel wire wheel - both are 70mm in diameter. Choose crimped wire for paint stripping, maintenance, cleaning light rust and removing small burrs. Twist knot brushes are more aggressive so better suited to heavier duty tasks such as removing weld scale, extra heavy rust and corrosion removal.