While meeting the required diver’s watch criteria, the U51 Diver Tourbillon comes with high technical features. In fact, the A-310 calibre is dedicated to efficiency, with a silicon lever escapement and with all bridges as plates made of titanium. Furthermore, Angelus’ engineers and watchmakers pushed the boundaries with a remarkable 5-day power reserve while keeping the 28,800 vibrations per hour (4 Hz) frequency, ensuring a high precision. Finally, the tourbillon cage is set on a ball bearing instead of pivots to gain in stability. Even though the U51 Diver Tourbillon is intended as a high-performance sporty timepiece, the skeletonised movement has been carefully decorated with sandblasted finishing, enhancing the natural colour variations of the titanium.
 

The 45 mm titanium case features two large screw-down crowns. The two-position crown at 4 o’clock is used for winding and setting the time, while the crown at 2 o’clock is used to rotate the unidirectional 60-minute rotating bezel. Opposite, at the 9 o’clock position, a helium escape valve is placed to ensure the watch’s water resistance to 300 meters (1,000 feet), even during saturation diving so the helium molecules could not make their way into the case under pressure.
 

Careful attention has been given to the aesthetic of the U51 Diver Tourbillon. The case is masterfully manufactured with a subtle interplay between sandblasted, brushed and polished surfaces, which takes full advantage of the titanium’s unique colours properties. The bezel of the case as the chapter ring are carved, recalling waves. The open display appeals with a contrasting chapter ring of stormy blue and striking orange colours. The hands, indexes and Arabic numerals are all filled with Super-Luminova for optimal readability.

The U51 Diver Tourbillon comes on a matching blue rubber strap embossed with an Angelus logo and a titanium folding buckle.