Automatic watches receive their power through the movement of the wearer’s wrist. They must be worn regularly, or the watch will stop. A winding box can be used to keep the watch wound if you do not wear it every day. It is in much higher demand than the traditional mechanical movements that need to be wound.
This is very close to the mechanical watch in terms of the method of time keeping, through the balance wheel and escapement, and a main spring to store energy. The difference between automatic and mechanical is that there is a weighted pendulum, or rotor attached to the movement. The rotor spins as the watch is worn, and is transmitted through to wind the main spring. This was designed so that the wearer wont need to wind the watch.