... course, primary can be good to get started ,also4-axis HJ450 Multi Flame WheelFree Flight FF Auto Balance Controller with ... Acceleration SensorDescription:- 100% brand new free flight controller, four axis Free Flight FF Auto Balance Controller,it can be used ... input and Six channel PWM output- Adopts three axis digital gyroscope and three axis digital accerleration sensor.- Auto-balance,quadcopter X ...