4" Premium grade Diamond polishing pad Dry (STADEA Super A) 5 Pcs + 1 backing pads concrete polishing set (One piece each of Grit 50, 100, 200, 400, 800 and one 5/8" 11 threaded rubber backer) for Concrete, countertop of concrete polishing. These diamond polishing Pads are aggressive. It is flexible and can polish either contoured surface like Ogee, Full Bullnose, Half Bullnose, Bevel, Demi or flat surface. Dry polishing pads can be used on low speed grinders or variable speed grinder or polishers. Dry diamond polishing is suitable for onsite or post-installation polishing need. Typically wet polishing creates watery mess and could have challenges performing wet polishing on site / post-installation. Dry polishing is easy and quick way to polish stone without any watery mess. It does generates dust, nasal protection is required during dry polishing. In general polishing starts with grit 50 diamond polishing pad, and is consumed more than higher grits diamond polishing pads. FAQ: 1) Can I use STADEA Super A dry polishing pads for Wet Polishing. Ans: Yes. STADEA Super A dry polishing pads are designed for dry polishing to dissipate heat faster and keep the temperate of polishing surface low. It can equally well be used for wet polishing. 2) Which backer threaded (5/8" 11 thread or M14 thread) is suitable for me? Ans: Countries using English system (Ex: USA, Canada etc) of measurement generally 5/8" 11 thread is standard. Countries using Metrics system (Ex: Australia, China etc) of measurement generally M14 thread is standard. You can also check the specification of polisher for the arbor thread size.