6pcs 4" Diamond Resin Bond Dry polishing pads (#50) Diameter 100mm 4 Inch , Total thickness 10.5mm, workable thickness 9mm Diamond Grit 50 Suitable for processing, repairing and renovating concrete floor, cement floor, terrazzo floor Dry or Wet Grinding or polishing, Dry working could be get better performance（Recommended RPM: 2200, the Maximum RPM: 4500） Special design for concrete polishing，Cost-effective