Feature:1. The SG90 9G micro servo weighs only 9g and has a torsion of 1.51.7kg/cm (4.8V6V).2. 40A ESC with security arming function, throttle calibration function, support multiple program methods.3. Compatible with lithium batteries(not included). The time can be changed to suit different brushless motors.4. Comprehensive protection, features low pressure cutoff protection/overheat protection/throttle signal loss protection.5. This kit includes 2217 KV1250 motor+8060 propeller+steering engine+40A XT60 ESC, can provides your RC helicopter better performance.Specification:Item Type: 2217 Motor KitMaterial: Metal+PlasticSG90 9g Servo Parameters:Size: Approx. 21.5 x 11.8 x 22.7mm/0.85 x 0.46 x 0.89inWeight: Approx. 9g/0.32ozNo-Load Speed: 0.12s/ 60 Degrees (4.8 V)Locked-Rotor Torsion: 1.5-1.7kg/cm (4.8V-6V)Working Temperature: -30-+ 60Dead Zone Setting: 5 MicrosecondsWorking Voltage: 4.8V-6V2217 Motor Specifications:Size: Approx. 27.8 x 32mm/1.1 x 1.3inShaft Diameter: Approx. 4 mm/0.16inKv: 1250kv40A ESC Specifications:Plug: XT60Continuous Current: 40APeaking Current: 55A (10S)Power Input: 2-4 Lithium Batteries (Not Included)BEC Output: 5V at 3A (Linear Regulator Mode-Linear Mode)Maximum Speed: 210,000 Rpm for 2-Pole Motor, 7000 Rpm for 6-Pole Motor, 35,000 Rpm for 12-Pole MotorApplication: Suitable for RC remote control helicopter.Package List:1 x Motor2 x Propeller2 x Steering Engine1 x ESC(Not Included Battery)1 x Motor Base1 x Coniform Head6 x Servo Arm1 x Tie10 x Screw2 x Rows of Propeller Washer