The Brushless Motor is special one for the electirc helicopter 450 class, it has the best performance for 3D fly. It will your best choice the 450 calss Helicopter. No. Of cells: 3-4x Li-Poly Max. efficiency current: 8 - 10.5 A ( gt;75%) No load current / 10 V: 0,5 A Current capacity: 40 A/60 s Dimensions:31 x 29 mm Shaft diameter: 3.17mm Weight: 64 g Recomended model weight: 450 class Ele. Heli. Recomended prop without