What you need to buy by yourself:(they are not included in the package):
1.Motor:BL2040 inner rotor brushless engine for boat
2.ESC:30A-50A for boat
3.Servo:9g servo for boat
4.Transmitter:2-3 channel controller
5.Battery for the boat:11.1v 3s 20c 2000mAh lipo battery
Package included: 1X RC Boat Kit(without motor,esc,servo,transmitter and battery)