seiko heren automaat snkd99k1Seiko Automatic 5 Sport SNKD99K1 Caliber 7S26 The 7S26 with day date indication is a mechanical caliber. The watch automatically charges itself while worn by converting the wearer's arm and wrist movements into energy. Movement of the watch causes the mainspring of the watch to be wound. This spring is the energy source. When the watch is fully charged, it has an energy reserve of approximately 40 hours. The ticking number of this automatic is 21,600