Sieko Men's SNK381K Stainless Steel Analog with Black Dial Watch

An automatic watch (also called a self-winding watch) is a mechanical watch, typically with a balance wheel escapement, whose mainspring is wound by the motion of the wearer's arm, instead of having to be wound manually every day. Whereas a quartz watch is powered by electricity, a mechanical watch is powered by a mainspring which must be rewound for the watch to keep time