Refers to the Seiko line of Kinetic watches. This innovative technology has a quartz movement that does not use a battery. Movement of the wrist charges a very efficient capacitor which powers the quartz movement. Once the capacitor is fully charged, men's models will store energy for 7-14 days without being worn. Ladies models store energy for 3-7 days. Of course, if the watch is worn every day the capacitor is continually recharged. The watch alerts the owner to a low capacitor charge when the seconds hand starts to move in two second intervals. Some of Seiko's Kinetic Watches have See-Thru CaseBacks, that use a clear, Hardlex crystal watch back to enable the wearer to view the kinetic movement.