IWC, Marine Chronograph series, model: IW370703, automatic mechanical movement, entire titanium watch, black matte dial • Diameter: 39.7mm, which is relatively small among chronographs and is friendly to slender wrists • Material: Full set of titanium metal (case + original titanium bracelet), lightweight and less likely to cause allergies • Movement: Cal.79320 automatic chronograph movement, 44-hour power • Functions: Three-eye timing, dual display of day and date, and speedometer outer ring • Water resistance: 120 meters, supports swimming, and is far more practical than the 30-meter water resistance of Portofino and Portugal