1. To grind, polish, clean for concrete, stone, marble floor 2.strong motor and reducer Features: 1. This construction machine adopts four heads contrarotating at high speed.2. Balance by hand, and can grind and polish different floors, such as concrete, marble, granite, stone and so on.3. With 4 phase gear reducer, make sure longer life.4. Intelligent adjustment of the speed, troubleshooting can ...