Upgraded version of the Jaeger-LeCoultre Master series! .1. Features a 6-position small seconds 7750 chronograph movement, with a frequency of 28,800 vibrations per hour, just like the genuine product.2. The entire watch has smooth lines, slim elegance, and a comfortable fit with a diameter of 40mm! .3. Sapphire double-sided anti-scratch mirror, made with Swiss standard-grade sapphire crystal glass, also covered with a super anti-reflective coating, showcasing the brand's exceptional quality! .4. Upgraded butterfly double push-button clasp!