This is an electrical part such as a motor, light, LED or switch.
Sharp little submarine motor is radio-controlled and comes with the controller and a charger; you need only to fix the motor to a boat with the included "magic tape", pop in batteries (4 AA batteries for the charger, and 1 9V battery for the controller; batteries not included), and go! The submarine motor must be charged first, so don't forget to hook it up to the included charger before using it!