This is a brushless motor and a motor joint set that is suitable for a 90-Class radio control helicopter. It is more powerful than any other motors for the same class due to its unique heat radiation structure of the battery. Pinion gear of screw pitch M9 can be attached to the motor joint. 0technical specs0 KV Level:560rpm Max Voltage:12cell Max Amp:100A Max Output:4200W Outside Diameter:53.9mm Length:87.2mm Shaft Diameter:6mm Weight:480g