UX SDR

The Sinn UX SDR was engineered for uncompromising performance in extreme environments, developed in collaboration with German special forces divers. Its unique oil-filled case not only delivers perfect legibility from any angle but also enables the quartz movement to function flawlessly at depths far beyond conventional dive watches—rated to an astonishing 5000 meters. The SDR variant features a black tegimented bezel, giving it a distinctive, tactical look compared to the standard UX.

Reference UX SDR models use the ETA 955.652 thermo-compensated quartz caliber, prized for its precision and reliability in harsh conditions. The oil-filled design eliminates fogging and parallax error, but it also means the case is fully sealed—battery changes require a specialized service from Sinn. The 44mm submarine steel case wears slightly smaller due to its slim profile and short lugs, making it suitable for a range of wrist sizes despite the diameter.

Collectors compare the SDR to the standard UX (with a steel bezel) and the UX S (with full black case), with pricing often reflecting bezel condition and completeness of box and papers. The black bezel can show wear more quickly than the steel version, so scrutinize for scratches or fading. Factory water resistance and oil integrity are critical; verify recent pressure testing and service records, as a compromised seal or depleted oil can affect both performance and value.