The Oris Aquis Date Calibre 400 measures 43.5 mm across and 13 mm thick, carries a 300-metre water resistance rating, and runs on an in-house automatic movement with a five-day power reserve. Those four figures define the watch more precisely than any marketing language could, and they explain why this reference sits at the centre of the modern Oris dive watch lineup of high-performance divers. It is a diver built for salt water and daily wear in equal measure.
The Aquis line has anchored Oris in the competitive sports-watch segment for well over a decade. Its identity rests on a few consistent signatures: a stainless-steel case with integrated lugs, a unidirectional rotating bezel, a screw-down crown, and luminous detailing applied to hands and indices for low-light legibility. The Calibre 400 edition keeps that silhouette intact and concentrates its changes where they matter most, inside the case.
A Movement Designed In-House
Oris developed Calibre 400 as a five-day automatic, drawing its energy from twin barrels arranged in series. The resulting 120-hour reserve means the watch can sit on a bedside table through a long weekend and still be running accurately when it returns to the wrist. The balance runs at 28,800 vibrations per hour, or 4 Hz, a frequency that supports stable rate-holding across the power band.
Anti-magnetism is the second pillar of the design. Oris states that the movement resists magnetic fields of up to 2,250 gauss, achieved through the use of special alloys in key components rather than a soft-iron cage. For anyone who spends working hours near laptops, speakers, or magnetic closures, that protection translates into fewer rate deviations and less need for regulation.
The third component of the package is a ten-year warranty, which Oris attaches to the Calibre 400 family and which is backed by recommended service intervals longer than the industry norm. Taken together, the reserve, the anti-magnetic construction, and the service philosophy describe a movement engineered around ownership longevity rather than short-term specifications.
Case Architecture And Water Performance
The 300-metre rating on the Aquis Date Calibre 400 is not decorative. It comes from a screw-down crown, a screwed case back, and a bezel assembly designed to seal under pressure. The unidirectional rotating bezel is fitted with a ceramic insert on many versions, and the minute scale is legible enough to time a decompression stop without squinting.
At 43.5 mm, the case sits in the full-size diver bracket, and the 13 mm thickness keeps it wearable under a shirt cuff in a way that chunkier 500-metre divers rarely manage. The lugs are short and curve downward, so the watch hugs the wrist rather than overhanging it. Bracelet versions use a steel link design with a folding clasp, while rubber strap versions are tailored to the lug width and suit warm-water use.
Dial And Bezel Execution
Oris offers the Calibre 400 Aquis with dials in several tones, including blue, green, and anthracite, with applied indices and a date window at six o’clock. The date aperture is subtle and does not break the dial’s symmetry the way a three o’clock window can. Hands and markers carry luminous compound for night diving and for the walk home after a late shift.
Wearability In Practice
A dive watch earns its place through versatility, and the Aquis manages the crossover from wetsuit to office without much fuss. The bezel action is firm enough not to drift when brushed against a jacket, and the crown guards protect the stem without making the winding action awkward. The combination of a 13 mm profile and integrated lugs means the watch photographs larger than it wears.
How The Aquis Fits The Wider Market
The modern diver segment is crowded with competent options, and buyers reasonably ask what separates one stainless-steel 300-metre watch from another. The answer here lies in the movement. Most watches at this price point run on outsourced calibres with a 38 to 80-hour reserve, and many of them carry a two-year warranty. The Calibre 400 shifts those reference points considerably.
Comparisons with other sports chronographs and divers are inevitable. Where a racing-inspired piece might emphasise a tachymeter scale and pusher ergonomics, the Aquis leans entirely into submersion capability and legibility. That focus is the point: the bezel, the crown, and the crystal are all specified for pressure and clarity rather than for show.
Versions of the Aquis Date Calibre 400 have appeared on rubber straps and on steel bracelets, and both configurations share the same case and movement. Buyers who plan to swim regularly tend to favour the rubber option for its grip when wet; those who want a single watch for all occasions often choose the bracelet for its formality.
Movement Specifications, Summarised
- Calibre: Oris Calibre 400, automatic winding
- Power reserve: 120 hours via twin barrels
- Frequency: 28,800 A/h, 4 Hz
- Anti-magnetism: up to 2,250 gauss using special alloys
- Warranty: ten years, per Oris
These numbers matter because they interact. A long reserve reduces wear on the movement from constant rewinding, and strong anti-magnetism keeps the long-term rate stable in everyday environments. The result is a diver whose accuracy does not depend on careful handling or frequent trips to a service centre.
The Case For Ownership
Watch collecting has shifted toward fewer, better-chosen pieces. The Aquis Date Calibre 400 responds to that shift with a specification sheet that reads like a commitment: five days of autonomy, meaningful magnetic protection, genuine dive certification, and a decade of warranty coverage. It is a tool watch in the honest sense of the term, built to be worn and used rather than stored.
For divers, the 300-metre rating and legible bezel do the practical work. For desk-bound wearers, the in-house movement and the manageable 13 mm thickness make it a daily companion that happens to be engineered for the ocean. Proportion, restraint, and mechanical substance remain the defining traits of the Aquis line, and the Calibre 400 version carries them further than any previous generation.
