This little beauty is useful should you want to take off your automatic watch occasionally or daily (like that would happen!) and not have to reset the watch when you go to wear it again. You see the automatic watch will only keep ticking while the mainspring inside the movement stores energy - which is generated through movement whilst wearing, or the manual winding of the screw crown.
Simply remove your watch, put it in place according to instructions and Bob's your uncle!
The winder comes with all the necessary accessories including an adaptor to plug in to your wall. This unit does not have the option of battery operation.