Works from the battery.Adjust the time by pulling up the knob and turning.<br /><br />♤ Pendant size: Watch: 2.7cm (1.06 inches Diameter)<br />♤ Wings:5.0x1.6(1.97x0.63in)<br />♤ Chain Length: 80cm (31.49 inches Length)<br />♤ Material: Alloy pendant watch & chain， all Nickel & Lead Free<br />♤ Package: All comes with nice gift packing!