Caliber 4R36The 4R36 Seiko caliber with day / date display is a mechanical caliber. The watch charges itself automatically when worn by converting the wearer's arm and wrist movements into energy. Movement of the watch causes the watch's mainspring to be wound. This spring is the energy source. Hand winding is also possible. When the watch is fully charged, it has an energy reserve of approximately 41 hours. The tick number of this machine is 21,600 per hour and the watch has 24 jewels. The 4R caliber is manufactured entirely in-house.Vending MachineThe watch has a silver colored case and a steel strap. Time and date are indicated on the watch. The watch is easy to read, even at night, because the hands glow in the dark. The clock has a diameter of 40 millimeters.