Watch Winders are mechanical boxes or cases that hold and occasionally turn, spin or rotate self winding watches so that they keep accurate time even when not on your wrist. Normally wearing an automatic watch is enough movement to keep it wound. But if you do not wear your automatic winding watch for several days or have more than one watch you may want a watch winder.
The best watch winders will keep that self-winding watch wound but also in a fashionable place ready for you to use it. Some have locking mechanisms with keys. Some can be placed in a safe with battery power. This makes for a secure, ready to use timepiece.