The Windows Collection is Minase's most iconic line, named after its defining feature: five or seven sapphire crystals set directly into each case, allowing light to pass through from every angle. Dial's Indices and case are hand-polished using Minase's exclusive Sallaz technique, delivering an exceptional depth and brilliance. Based on ETA 2671 ébauches, this high-end execution displays hand-finished surfaces with perlage, blue screws, bridges with diamond polished bevels. The brand's drill head logo is engraved on the black gold plated rotor. 21 Jewels. Frequency 28’800 vibrations/hour (4 Hz), 42 hours power reserve. Built around a unique «case-in-case» construction, the Windows is a masterclass in Japanese micro-engineering — where every surface, every angle, is designed to interact with light.The Windows Collection is Minase's most iconic line, named after its defining feature: five or seven sapphire crystals set directly into each case, allowing light to pass through from every angle.