For wet polishing marble and granite. Wet polishing marble and granite.Velcro backing allows for fast pad changes.Pad backs are color-coded for easy grit size identification. Use on Electric or Pneumatic Polisher.Diameter:4''(100mm).Grit size:50#,100#,150#,200#,300#,400#,500#,800#,1000#,1500#,2000#,3000#,buff. Premium Quality,Spiral Type.