Iwc, model: IW371447, Portuguese series 61 serial number, 40.9mm in diameter, black dial with silver hands. Classic design never goes out of style. The most popular Portuguese watch from IWC, the black dial, looks even more exquisite and unique when worn 1. Design and appearance Case and Dimensions: It features a 40.9mm stainless steel case with thin and elegant lines and a thickness of only 12.3mm, making it highly suitable for formal wear. Dial details: The black radial dial is paired with the classic "railway minute ring". At 12 o 'clock, there is a 30-minute chronograph sub-dial, and at 6 o 'clock, there is a small seconds sub-dial. The Arabic numeral hour markers are paired with willow-leaf-shaped hands, making the time reading clear and full of retro texture. Strap and buckle: It is equipped with a black alligator leather strap and a stainless steel pin buckle. It is water-resistant to 30 meters and is only suitable for daily wear. It does not support swimming, diving and other scenarios. 2. Movement and Performance Movement configuration: Equipped with the IWC Cal.79350 automatic chronograph movement (modified based on the ETA 7750 movement), with a frequency of 28,800 vibrations per hour and a power reserve of approximately 44 hours, it features chronograph functionality. Case back design: It adopts a solid case back design, with the IWC logo engraved on the back, and is paired with a scratch-resistant sapphire crystal.