Designed for professional and heavy-duty tasks., Up to 13300 RPM. Revolutionize Your Fleet with Premium coating removal cup wheels Concrete Grinding Wheel Diamond Grinding Cup Wheel For Hard Concrete Concrete Grinding Disc About this item. Specification: 4.5 Inches, 16/20 grit, 15 segments,7/8 arbor, wet and dry use, especially suited for extremely hard concrete... Aggressive and long using life for medium/ hard/ super hard concrete floor PCD DIAMOND GRINDING CUP WHEEL Heat dissipation design helps improve the processing quality and extend service life of the segments