Chronograph 6139-7100

AutomaticAutomaticA mechanical movement wound by a rotor as the watch moves on the wrist. day-date chronographChronographA watch function for starting, stopping and resetting an elapsed-time measurement independently of the ordinary time display. in the Seiko 6139 family. Documented executions retain this exact 6139-7100 case reference; a complete production span has not been established.