TUDOR's new Black Bay 31/36/39/41 Collection features fixed steel bezels and comes in four sizes 31mm, 36mm, 39mm and 41mm. These watches have Manufacture Calibres, certified by COSC as chronometers, and a non-magnetic silicon balance spring. The larger and medium-sized movements have a 70-hour power reserve, while the smaller movements have a 50-hour power reserve. The Black Bay 31/36/39/41 models depart from TUDOR's tool watch spirit and offer a sophisticated, versatile, unisex look. The cases feature a combination of finishes, with polished and domed sides, a curved design, and a curved winding crown. The five-link bracelet comes with a TUDOR "T-fit" clasp, with rapid adjustment, in all sizes. The watches borrow elements from TUDOR's dive watches from the 1950s and 1960s, such as the angular "Snowflake" hands. The dials come in blue, anthracite, or light champagne-coloured, with or without the diamond-dot setting, and have a contrasting colour minute track.