IWC, IWC Portuguese collection, model: IW371606, automatic winding, stainless steel, case diameter: 41mm Model: IW371606 (Portuguese Series Automatic Chronograph Watch, Blue Dial Steel version) Case: 316L stainless steel, 41mm in diameter, 13.1mm in thickness, classic barrel-shaped bezel Strap: Original black matte alligator leather strap with pin buckle Dial: Deep sea blue radiating pattern dial, Arabic numeral hour markers, upper and lower double sub-dials layout (30-minute counter at 12 o 'clock and small seconds counter at 6 o 'clock), track-style minute scale Movement configuration ⚙️ It is equipped with the IWC self-produced Cal.69355 automatic chronograph movement It features 211 parts, 33 gemstone bearings, a swing frequency of 28,800 VPH, a power reserve of 46 hours, a transparent back cover, and a plate with classic fish-scale patterns from all over the world and Geneva finishing Functions: Minute and minute timekeeping, central large seconds chronograph at 3 o 'clock, dual-dial chronograph reading, 30-meter water resistance for daily use (water resistance standard for dress watches) Style positioning: IWC's benchmark formal chronograph. The blue dial is the most popular color in the entire IWC series. It is suitable for both business and casual wear and is the best-selling model of IWC Blue dial color: The sunray blue dial changes color with light, making it the most valuable color for Portuguese watches and having a higher recognition rate than the white dial model Retro Portuguese design: Inspired by the first-generation version of Marine chronographs, with a narrow bezel and a large dial, it exudes a retro gentlemanly style New optimization: The 69355 movement replaces the old purchased movement, with comprehensive upgrades in stability and energy storage