The aluminum alloy gearbox and planetary gear driver are capable of reaching a remarkable flat grind to produce smooth surfaces as well as a powerful repairing scratches function. There is a folding handle and split body design for a more convenient way to carry and transport the machine. The automatic leveling system has excellent flexibility to evenly touch the floor and perfectly balance the machine. Through the integrated system of the suction port, the machine grind and polish wet or dry. There are three different models available for this 21 inch grinder.