Works from the battery.Adjust the time by pulling up the knob and turning.<br /><br />♤ Watch size:4.7x3.8cm(1.85x14.96in)<br />♤ Chain Length: 80cm (31.50 inches Length)<br />♤ Material: Alloy pendant watch & chain， all Nickel & Lead Free<br />♤ Package: All comes with nice gift packing!