Seiko Watch SRPE15J1

The 4R35 Seiko calibre with date display is a mechanical calibre. While worn, the watch automatically recharges itself by converting the wearer's arm and wrist movements into energy. Movement of the watch causes the watch's main spring to be wound up. This spring is the energy source. Hand winding is also possible. When fully charged, the watch has a power reserve of about 41 hours. The tick rate of this automatic is 21,600 per hour and the watch has 23 jewels. The 4R calibre is manufactured entirely in-house.