OX Tools 4 Inch Double Row Diamond Cup Grinder OX PCDT 4 (15300 Max RPM 7 8 Arbor Concrete Masonry Stone Grinding Surface Prep Disc) Tool Set High Friction Dry Concrete Grinding: Dissipating High Friction Dry Concrete Grinding: Dissipating extreme friction induced heat on hard troweled slabs and dense aggregate floors without overheating diamond segments Perma SHIELD Non Stick Armor: High performance surface shield blocks pitch gumming Wet or Dry Utility: Versatile design engineered specifically for high velocity dry grinding or wet suppression applications 300 RPM rating and heat treated steel core ensure robust durability under heavy torque loads for both wet and dry construction applications