This Bach rotor was designed by the concept of being the strongest and fastest rotor on the earth. And we created the best rotor you have ever seen.By the high speed rotation and our original vibrating object which was customized by the data of analyzing a ratio of the motor and weight , this rotor can produce twice as strong as the conventional rotor. The Bach rotor also can express 50 different vibrating patterns by R1 Controller.You will need the R1 Controller sold separately. See item A00155