1.With counter rotating planetary with steel gears 2.Very easy to handle 3.Powerfully motors ModelHercules 530Horse ... , cement floors, etc) 2.With “counter rotating planetary with steel gears”. Very easy to handle, reliable, rubust and long-lasting. 3 ... with “belt driver” Extremely strong Floor Grinding machines with metal gears Planetario head. No belt to break! POWERFULL MOTOR MONO-PHASE ...