Oris Calibre 400 Explained: Specs, Power Reserve, Service and the Watches That Carry It

Oris launched the Calibre 400 in October 2020 with a single clear message: the mid-tier Swiss manufacturer had its own in-house movement at last. Not a licensed ETA, not an outsourced ébauche — a movement designed and assembled at the Oris factory in Hölstein, Switzerland, with a 120-hour power reserve, a factory-specified 10-year service interval and anti-magnetic resistance strong enough to rival the resistance specs on movements costing two or three times as much.

Four years on, the Calibre 400 has become the benchmark against which every other automatic in its price bracket is measured. If you are researching an Oris purchase, trying to understand what the Cal 400 actually does differently, or comparing it to the Tudor MT5602 or Omega’s Co-Axial family, this is the guide for you.

The specs at a glance

Before getting into the engineering, here are the headline numbers that make the Calibre 400 stand out:

Power reserve	120 hours (5 days), twin barrels
Frequency	4 Hz / 28,800 vph
Jewels	21
Accuracy	−3 / +5 seconds per day
Anti-magnetic	>2,250 gauss; 30+ non-ferrous components
Escapement	Silicon escape wheel and pallet fork
Rotor	Unidirectional, low-friction slide bearing
Service interval	10 years recommended
Warranty	10 years
Launched	October 2020 (first watch: November 2020)

At −3/+5 seconds per day, the Calibre 400 does not carry COSC chronometer certification, but its specified accuracy window falls entirely within the COSC tolerance of −4/+6 seconds per day. Oris chose not to pursue certification — a business decision that keeps costs down without compromising the movement’s real-world performance.

Twin barrels and the 120-hour power reserve

The headline figure on the Calibre 400 is its 120-hour power reserve — five full days from a single wind. That is not the norm for a 4 Hz automatic movement in this price range: a single-barrel ETA 2824-2, the most common workhorse movement in sub-$5,000 Swiss watches for decades, delivers around 38 hours. Even the most capable single-barrel automatics in this tier rarely exceed 60–70 hours.

Oris achieves the five-day reserve through twin series-wound barrels — a configuration more common in high-end and complications movements. Running two barrels in series means each one stores and releases energy independently; together they provide the extended mainspring length needed to sustain 120 hours of running time while maintaining consistent torque delivery across the full power cycle. Consistent torque matters because erratic mainspring tension is the primary cause of positional accuracy variation in mechanical movements.

For the wearer, 120 hours of reserve has a practical benefit beyond the engineering: you can set an Oris Cal 400 watch on Friday evening and it will still be running — and still accurate — when you reach for it on Wednesday morning. In a world of weekend sports watches, that kind of reserve turns a dedicated dive or pilot’s watch into a set-and-forget daily rotation piece.

Anti-magnetic construction: silicon and non-ferrous components

The Calibre 400 is specified to resist magnetic fields above 2,250 gauss without requiring an inner soft-iron Faraday cage. That figure puts it ahead of most Swiss automatics in its price range and is achieved through a combination of silicon and non-ferrous component design rather than case-level shielding.

The escape wheel and pallet fork — traditionally the two parts most vulnerable to magnetisation in a lever escapement — are produced from silicon. Silicon is paramagnetic, which means it does not retain a magnetic charge the way hardened steel does. More importantly, silicon is also self-lubricating at the microscopic level and far stiffer than steel at equivalent thicknesses, which lets Oris machine thinner, lighter escapement parts that oscillate more efficiently.

Beyond the escapement, the Cal 400 incorporates more than 30 components made from non-ferrous or actively anti-magnetic materials. The cumulative effect is a movement that can be worn around MRI scanner environments, substation equipment, speaker stacks, and virtually any everyday source of magnetic interference without the accuracy degradation that would affect a conventional steel-geared movement.

For divers in particular, this matters: submersible dive watches spend time near equipment and hull materials that generate ambient magnetic fields. Oris’s anti-magnetic brief for the Cal 400 was partly written with the Aquis line’s professional dive heritage in mind.

Service interval and 10-year warranty

Oris specifies a 10-year service interval for the Calibre 400 — double the typical five-year recommendation on a conventional mechanical movement. The movement ships with a 10-year manufacturer’s warranty to match, the longest standard warranty in its category at the time of launch.

The extended service interval is made possible by several design choices working in combination. Silicon’s low friction at the escapement and its resistance to wear means the escape wheel and pallet fork do not require lubricating oil the way steel parts do — and it is oil degradation over time, not mechanical wear on steel, that typically drives the five-year recommendation on conventional movements. The Cal 400 also uses a low-friction slide bearing on its unidirectional rotor rather than a ball bearing, which further reduces the lubrication points that need periodic replacement.

In practical ownership terms, a 10-year service interval halves the cost of ownership over a watch’s lifetime compared to a movement requiring service every five years. Oris service costs vary by retailer and market, but a full service on a Cal 400 movement typically runs between $350 and $600 at authorised service centres. Halving the frequency of that cost matters over a decade of ownership.

How the Calibre 400 compares to rival movements

The Calibre 400’s main competitors in the $3,000–$5,000 automatic sector are the ETA 2824-2 (and its Sellita SW200 equivalent), Tudor’s MT5602, and Omega’s Co-Axial calibres in the 8800 family. Here is how they compare on the key ownership specs:

Movement	Power reserve	Anti-mag	Service interval	Frequency
Oris Calibre 400	120 hours	>2,250 G	10 years	28,800 vph
ETA 2824-2	~38 hours	~60 G	5 years	28,800 vph
Tudor MT5602	70 hours	~150 G	5 years	28,800 vph
Omega Cal. 8800	55 hours	>15,000 G (METAS)	10 years	25,200 vph

The ETA 2824 comparison is instructive: the Cal 400 offers more than three times the power reserve, double the service interval, and far superior anti-magnetic resistance — in a watch that costs only modestly more than an ETA-powered equivalent. That is part of why the industry paid close attention when Oris launched it.

Tudor’s MT5602 — the movement inside the Black Bay 58 and most of the Black Bay range — is a genuinely excellent in-house movement with 70 hours of reserve and a COSC chronometer certificate. However, it runs in steel and offers substantially less anti-magnetic resistance than the Cal 400. For a detailed breakdown of Tudor’s manufacture calibres across the full range, see our dedicated guide.

Omega’s Co-Axial 8800 is arguably the most technically advanced movement in the peer group: it carries METAS Master Chronometer certification with anti-magnetic resistance above 15,000 gauss and a 10-year service interval. But it does so in a watch that starts above $5,000 for the Seamaster Planet Ocean entry point. The Cal 400 sits in a different price band entirely and represents genuinely exceptional specification for the money.

The watches that carry Calibre 400

The Cal 400 debuted in the Aquis Date and has since spread across multiple lines. Here is where you currently find it:

Oris Aquis Date (41.5mm)

The original home of the Cal 400, the Aquis Date launched alongside the movement in late 2020. It runs at 41.5mm diameter with a 300m water rating, a date complication at 6 o’clock and the integrated bracelet or rubber strap option. Launch retail in the US was $3,300 on rubber and $3,500 on bracelet. The Aquis Date remains the most widely available Cal 400 reference and the best entry point into the movement for buyers who want a diver with clean modern proportions. Our Oris Aquis Date vs Tudor Pelagos 39 comparison covers how the Cal 400 holds up against Tudor’s titanium diver in a head-to-head.

Oris Divers Sixty-Five Calibre 400 (38mm and 40mm)

Oris introduced the Cal 400 to its Divers Sixty-Five vintage-inspired line in 2022 and 2023. The 38mm no-date in a limited green dial variant launched at $3,900, while the 40mm Divers Sixty-Five 12H Calibre 400 (featuring a 12-hour reference bezel rather than the traditional dive scale) has been available from $3,500 on leather strap and $3,700 on bracelet. The Sixty-Five pairing is significant because it brings the Cal 400’s five-day reserve and 10-year service spec into a smaller, more formal-friendly package.

Oris ProPilot X Calibre 400 (39mm)

The ProPilot X is perhaps the most technically distinctive host for the Cal 400: its ultra-light rubber-composite case brings the 39mm watch to under 45g including strap. UK retail has been in the £4,050 range. If the Aquis Date is the diver’s Cal 400, the ProPilot X is the aviator’s Cal 400 — emphasising the movement’s anti-magnetic credentials in a field environment that often involves cockpit avionics and magnetic compass systems. For more on Oris’s pilot watch line, our Oris ProPilot Calibre 111 deep-dive covers the brand’s ten-day pilot movement as a point of comparison.

Oris Aquis Professional (AquisPro) 49.5mm

The AquisPro is Oris’s professional diving instrument — 49.5mm, 500m water resistance, helium escape valve — and it also runs on the Calibre 400. In a professional dive tool rated to half a kilometre depth, the 120-hour power reserve means saturation divers working extended bell runs do not need to surface a watch before knowing whether it will still be running.

What the Calibre 400 means for buyers

The practical case for choosing a Cal 400 watch over an ETA- or Sellita-powered alternative comes down to three ownership advantages: the five-day reserve, the 10-year service cycle, and the anti-magnetic construction. At sub-$4,000 retail prices, no other Swiss manufacture movement delivers all three simultaneously.

The five-day reserve means a Cal 400 watch stays wound through weekends, business trips and watch rotation without a winder. The 10-year service window means you will likely service the watch once rather than twice before a decade is up — saving between $350 and $600 per avoided service. And the silicon anti-magnetic construction means the movement’s rated accuracy is maintained in environments where a conventional steel escapement would degrade.

There are trade-offs. The Cal 400 does not carry COSC certification, so it cannot officially claim the chronometer label. Its anti-magnetic rating of 2,250 gauss, while well above daily-life requirements, falls short of the 15,000+ gauss benchmark that Omega’s METAS-certified calibres achieve. And Oris remains a mid-tier brand — a fact that affects resale values compared to a Rolex or Omega regardless of how good the movement is.

What the Calibre 400 gives you is genuine manufacture credibility, outstanding practical specifications and a 10-year warranty — packaged in watches that retail between $3,300 and $5,000. For that combination of spec and price, it stands alone in its tier.

Frequently asked questions