Discover MB&F's precision with the Horological Machines (ref. 91.SRL.BU), a refined timepiece that blends thoughtful design with reliable performance. A study in proportion and durability: measuring 47 mm in diameter, with a thickness of 23 mm, defined by a round silhouette. The caseback is open, and the crystal is sapphire, delivering water resistance to 3000 meters. The dial composition is deliberate and legible: a see-through tone, framed by mixed hour markers, and dauphine hands. Beneath the caseback lies dependable performance: the HM9 caliber. Released in a constrained run, appealing to focused collectors. Initial production year: 2021. Comfort and balance define the wearing experience, making it an easy daily companion. Subtle transitions between textures elevate the overall impression. For buyers researching specifications and real-world impressions, this reference stands out for coherent design, dependable mechanics, and lasting relevance within modern horology.