The SDR version of Sinn’s U1 features a bezel with Black Hard Coating on a TEGIMENT Technology basis.With the diving watch U1, Sinn engineers succeeded in developing a diving watch in which the quality of material and design gives it superior resistance to external influences under extreme conditions of use.In their search for a steel with the desired resistance, the Sinn engineers found what they were looking for at the German submarine manufacturer ThyssenKrupp Marine Systems: the steel manufacturers supply small quantities of the original steel of the current German submarine production exclusively to Sinn for making diving watches — the very steel of which the external hulls of the German Navy’s new submarine class 212, which currently represents the most advanced non-nuclear submarines in the world, are made. This original submarine steel is not only extraordinarily seawater-resistant but is also of the highest non-magnetic quality without any residual magnetism.To ensure reliably that the rotating bezel of the diving watch does not detach under harsh impacts, it is attached as a captive bezel to the central part of the case. The ratcheting is mounted on a sophisticated bearing system. Slightly radially offset locking pin positions protect the toothed ring, ensure reliable function over the long term and facilitate firm and secure ratcheting with a rich clicking sound.The water-resistance and pressure resistance of 100 bar (= 1000 m water depth) was certified for the diving watch U1 by DNV GL. The safety test pressure used for this purpose was 125 bar.As per unknown date this watch is powered by a Sellita movement instead of ETA.
