Unexpectedly good! Testing the Oris masterpiece, the Oris Aquis Date Calibre 400

After five years of development, Oris proudly launched their new in-house movement, the Caliber 400, which boasts no maintenance for 10 years and even comes with a 10-year warranty. The Oris Aquis Date Caliber 400, which is equipped with this mechanism that not only has a power reserve of approximately five days but also has high magnetic resistance, was put through a performance test this time.

Measurement results worthy of being described as a "top-level watch", long power reserve, anti-magnetic properties, long service life

　At first glance, this model appears to be a "normal" Oris Aquis Date. What lies within is not immediately apparent. From the outside, the familiar gradient dial, which gradually changes color from vibrant blue in the center to almost black at the edges, is immediately recognizable. Surrounding it is the unidirectional rotating bezel, signaling the Aquis Date's functional diver's watch. The knurled ratcheted ring, which rotates in 30-second increments, is fitted with a scratch-resistant dark blue ceramic inlay. This, along with the luminous Super-LumiNova-coated hour markers and hands, is designed for safe diving.

　At the bottom of the dial, just below the water resistance indicator (30 bar/300 meters), you'll find a "5-day" power reserve display. This is an understatement, showcasing the technical capabilities of the Caliber 400, which Oris calls "revolutionary." This display is clearly visible through the screw-down transparent caseback. Its unique design, free of any "high-tech" trademarks like the red rotor that Oris movements are known for, makes it immediately clear that this is a new movement. In addition to the in-house manual calibers 110 through 115, the new in-house automatic Caliber 400 joins the ranks of mass-produced movements from major suppliers like Sellita. Oris places great importance on offering quality watches at affordable prices. Therefore, the Caliber 400 is not intended to replace existing standard movements, but rather to complement them and not increase the prices of models equipped with existing movements.

Caliber 400: A symbol of the brand's pride

　Oris developed the Caliber 400 in-house, tailoring its performance to the unique character of Oris watches and the demands of its customers. This automatic movement was redesigned from the bottom up, with every detail thoroughly tested. COO Beat Fischli, who led the team developing the new caliber, explains that the goal was to design a highly efficient and robust movement. The result was one that met modern needs. Offering the highest quality at an affordable price and delivering true value to customers, as well as emphasizing the sustainability concept that Oris has pursued in numerous models over the years, these were ambitious goals rooted in the brand's philosophy and also met modern needs.

　The result of five years of development, this movement boasts a solid foundation that is immediately apparent through the transparent case back. The matte finish on the bridges and the meticulous finishing on the hollowed-out rotor showcase the brand's technical expertise and give the Caliber 400 a robust appearance. For the automatic rotor, Oris has eliminated the ball bearings, replacing them with a smooth-running sliding bearing, consisting of a stainless steel shaft running through a lubricated cylinder. Engineers realized that issues with single-winding mechanisms were related to the ball bearing that allows the winding rotor to rotate freely. The Caliber 400's winding system provides efficient single-winding, and the sliding bearing reduces wear.

　　The Caliber 400's automatic winding mechanism can run for approximately five days when fully wound. Its frequency remains remarkably stable throughout this time. The oscillation averages 300° when fully wound and 240° by the fifth day. Achieving this level of performance requires two large barrels and a long mainspring. The two barrels are arranged in series and occupy nearly half of the movement. Each barrel stores approximately 60 hours of power. This system ensures efficient power management, and its low torque reduces pressure on the gear train, minimizing wear. A redesigned gear train also improves power transmission efficiency. Overall, the movement consumes 85% of the power provided by the barrel, compared with the usual 70%.

　The power is transmitted to an entirely new escapement. The precisely interlocking pallet and escape wheel are crafted from silicon, while the pivots and balance wheels are made from non-ferrous alloys. More than 30 of the 135 components are made from this same material, making the Caliber 400 90% less susceptible to magnetic fields than a typical Swiss movement. Oris, in collaboration with Laboratoire Dubois in La Chaux-de-Fonds, subjected the Caliber 400 to stresses of 2250 gauss per day. The movement subsequently achieved accuracy within 10 seconds per day. For comparison, the soft-iron cage used by Rolex in its Milgauss is resistant to magnetic fields up to 1000 gauss. The current ISO 764 standard defines a movement as resistant to 200 gauss with no deviation of more than 30 seconds per day. While this standard seems a bit outdated, the Oris Caliber 400 still recorded a daily deviation of one-third even after being exposed to a magnetic field 11 times stronger.

　We conducted the following test on the Aquis Date Caliber 400 in our office. We subjected the watch to a magnetic field of approximately 1000 gauss, the same strength most people experience in their daily lives, for a set period of time. During the test, the amplitude dropped significantly and some readings became unstable. However, this is normal and has been observed in other magnetic resistance tests. After the magnetic field was removed, the amplitude returned to normal within a short time. As the brand claims, it settled at -7 seconds per day. This demonstrates high reliability and is an above-average result. Once the watch was removed from the magnetic field, everything returned to "normal."

　When this test watch was worn in an almost fully wound state during daily wear, it showed a daily deviation of approximately 3 seconds. This is roughly the same as the value measured using a timegrapher. On the second and third days, stability improved, with the daily deviation reaching approximately 2 seconds. On the fourth day, almost no change was observed, and on the fifth day, a slight delay was observed, but as mentioned above, the results were very good in terms of oscillation angle and position deviation. This is thought to be largely due to the regulator control system, a unique system already used in in-house hand-wound movements.

10-year warranty on the Caliber 400

　Oris is so confident in this cutting-edge technology that it offers a 10-year warranty on the Aquis Date Calibre 400 and all future watches equipped with this movement. "The Calibre 400 sets a new standard," says Oris CEO Rolf Studer, proudly adding, "There's nothing like it. Thanks to the structural solutions of the Oris Aquis Date Calibre 400, we can not only offer a 10-year warranty, but also provide an equally long service service."

　The Oris Aquis Date Caliber 400 has undergone water resistance testing, as is customary for professional divers. Contributing to its 300m water resistance are the screw-down caseback and crown, which are protected by a screw-down crown guard. The large crown, with its side ridges, is easy to grip and unlock. The central position allows for fast date adjustment. As usual, the date is displayed at 6 o'clock, but this time it features white numerals on a black ring that complements the black tones of the gradient dial, and the aperture is larger. This means the date ring is larger than before and requires more power to move. The date typically begins to move approximately one hour after midnight, at which point it jumps to the next display almost precisely. When adjusting the time, a slight jump in the minute hand was observed when pulling out the crown. The Caliber 400 features a modern stop-seconds function, which allows for accurate setting to the second by first moving the minute hand back slightly before setting the watch.

　The Aquis Date Caliber 400's high-quality stainless steel bracelet features Oris' proprietary strap change system, which is now almost standard. A secure flap engages the bar and locks securely into place with an audible click. A fingernail is all it takes to unlock it. The folding clasp opens with the pushers on both sides and includes a 20mm diver's security and extension. For those who prefer to wear rubber straps in the water, the "quick strap change" system is a convenient solution.

Caliber 400: Meets the demands of everyday use

　The Aquis Date is a professional diver's watch, down to every link on its stainless steel bracelet. Significantly, it was the first model to feature the revolutionary Caliber 400. Robust, stylish, technologically advanced, and affordable, it embodies Oris' philosophy. Equipped with Caliber 400, this model offers customers added value, including stable measurement results, a long power reserve, reliable anti-magnetic properties, and a long service life. It's a top-tier watch that not only resembles the tough, elite athletes in both appearance and character, but also fully meets the demands of everyday wear.

Accuracy stability test

*This article is a translation of the German version of Kronos.