Most comparisons of these four movements are written for collectors deciding which watch to buy. This one is written for the people who have to specify a movement for a production run — product managers, sourcing teams and engineers who need to know what changes in the case, the schedule and the after-sales plan when one caliber is chosen over another.
We work with all four platforms in OEM and ODM programs, and have been doing so in Dongguan since 2009. Where a figure below comes from the movement maker’s published specification, we say so. Where it comes from our own project experience, we say that too. Where the honest answer is “it depends on the batch and the grade”, we won’t pretend otherwise.
If you are still deciding between quartz and mechanical, or between Swiss, Japanese and Chinese origin, start with our movement selection guide first. This article assumes you are already choosing between specific automatic calibers.
The Four Calibers at a Glance
| ETA 2824-2 | Sellita SW200-1 | Miyota 9015 | Seiko NH35 | |
|---|---|---|---|---|
| Maker | ETA (Swatch Group) | Sellita | Miyota (Citizen Group) | Seiko Instruments, sold under the TMI brand |
| Diameter | 25.6 mm | 25.6 mm | 26.0 mm | 27.4 mm |
| Height | 4.6 mm | 4.6 mm | approx. 3.9 mm | 5.32 mm |
| Frequency | 28,800 vph (4 Hz) | 28,800 vph (4 Hz) | 28,800 vph (4 Hz) | 21,600 vph (3 Hz) |
| Jewels | 25 | 26 | 24 | 24 |
| Power reserve | approx. 38–42 h | approx. 38–41 h (SW200-2: approx. 65 h) | approx. 42 h | approx. 41 h |
| Winding | Bi-directional | Bi-directional | Uni-directional | Bi-directional (Magic Lever) |
| Maker’s accuracy spec | By grade | By grade (see below) | −10 to +30 s/day | −20 to +40 s/day |
| Availability to brands outside the maker’s group | Effectively ended | Available | Available | Available |
Specifications are the makers’ published figures as commonly documented; always confirm against the current technical sheet for the exact variant you order (date/no-date, date position, grade).
ETA 2824-2 and Sellita SW200: Mostly a Supply Question Now
Mechanically, the SW200-1 was designed as a dimensional match for the 2824-2. Same diameter, same height, same beat rate, one extra jewel. In practice, a case, dial and hand set engineered around one will accept the other. Watchmakers who service both tend to describe the differences as minor.
The real difference is availability. ETA has steadily withdrawn supply to brands outside the Swatch Group, and the 2824-2 is no longer something a new production program can reliably plan around. Most “2824-type” movements going into new watches today are SW200s. If your existing collection was engineered around the 2824-2, the SW200 is the lowest-disruption path forward: in most cases the case does not need to change.
The 2026 change: SW200-2 Power+
In February 2026 Sellita introduced the SW200-2 Power+, raising the power reserve to roughly 65 hours while keeping the 4 Hz frequency. It keeps the SW200’s external architecture, and the two versions are currently being produced in parallel, with the -2 expected to gradually replace the -1.
For a brand, two practical points matter more than the headline number:
- The movement fits; the parts do not. The SW200-2 can replace an SW200-1 in the same case, but many internal components are new and are not interchangeable with the -1. If one model ships with both versions across different batches, your service partners need to stock and identify parts for both.
- Specify the version in writing. During the transition period, “SW200” on a purchase order is ambiguous. State SW200-1 or SW200-2, the grade, and the date configuration explicitly.
Swiss Grades: What You Are Actually Choosing
Both the 2824-2 and the SW200 are offered in four grades. The grade, not the caliber name, is what decides how consistent timekeeping will be across a batch.
| Grade | Adjusted in | Published accuracy range |
|---|---|---|
| Standard | 2 positions | ±12 s/day average, up to ±30 s/day |
| Special (Elaboré) | 3 positions | ±7 s/day average, up to ±20 s/day |
| Premium (Top) | 5 positions | ±4 s/day average, up to ±15 s/day |
| Chronometer | COSC-certified | COSC criteria |
The higher grades also differ in components — for example the shock-protection system and balance — and in available decoration levels. Higher grades also tend to carry longer and less predictable lead times than Standard grade.
A practical rule we use with clients: decide the acceptable timekeeping range for the finished watch first, write it into the specification, and then choose the grade that can meet it. Choosing Standard grade and expecting Top-grade results is one of the most common sources of disputes at final inspection.
Miyota 9015 and Seiko NH35: Not Interchangeable
These two are often listed side by side as “the Japanese options”, but from an engineering point of view they lead to different watches.
- Case profile. At roughly 3.9 mm the 9015 allows a noticeably slimmer case than the NH35 at 5.32 mm. If the design brief calls for a dress-proportioned automatic, the NH35 usually cannot achieve it.
- Diameter and dial. The NH35 is 27.4 mm across; the 9015 is 26 mm. Dial feet positions, date window position and stem height are all different. Switching between them is a case and dial redesign, not a part swap.
- Seconds hand. The 9015 beats at 4 Hz and the NH35 at 3 Hz. Most customers will not count, but a smoother sweep is visible side by side.
- Winding. The NH35 winds in both directions through Seiko’s Magic Lever system; the 9015 winds in one direction only. Wearers who are less active may notice the difference in how quickly the watch reaches full reserve.
- Cost. The 9015 generally costs a brand meaningfully more than the NH35, and that difference carries through to the final unit cost.
- Published accuracy. Miyota specifies −10 to +30 s/day for the 9015; TMI specifies −20 to +40 s/day for the NH35. Individual movements often perform better than the published range, but the published range is what you can hold a supplier to.
Both families have useful variants. The 9039 is the no-date version of the 9015, which matters for symmetrical dial designs; the 9075 adds a true GMT function. On the Seiko side, the NH36 adds day-date and the NH38 is an open-heart version. If a collection will include several models, picking a family with the variants you need can keep case engineering largely shared across the range.
Choosing Between the Four
| If the priority is… | The usual direction |
|---|---|
| “Swiss movement” on the product story, with existing 2824-based tooling | Sellita SW200 (specify -1 or -2 and grade) |
| Swiss movement plus longer power reserve for a new collection | SW200-2 Power+, with parts planning for service |
| Slim automatic case at a mid-market price | Miyota 9015 (or 9039 for no-date) |
| Robust everyday automatic with the lowest movement cost in this group | Seiko NH35 / NH36 |
| Shared engineering across a multi-model collection | The family with the variants you need (Miyota 90xx or Seiko NH3x) |
What to Put in the Specification
Whichever caliber you choose, the following details prevent most misunderstandings later:
- Full caliber designation, including version (for example SW200-1 vs SW200-2, NH35 vs NH36)
- Grade for Swiss movements
- Date or no-date, date position and date-wheel color
- Acceptable timekeeping range for the finished watch, and how it is measured
- Rotor finish or customization, if any
- Requirement for genuine movements sourced through authorized channels, with packaging and markings retained for verification
On that last point: genuine NH35s may carry either SII or TMI markings on the rotor — both are legitimate Seiko production. Unmarked or relabeled movements sold as “2824-compatible” are a different matter, and are covered in our movement sourcing guide.
FAQ
Is the Sellita SW200 as good as the ETA 2824-2?
For production purposes, yes. The two are dimensionally interchangeable and close in specification. Grade matters far more than the name on the bridge.
Can I still order the ETA 2824-2?
For brands outside the Swatch Group, reliable supply of new 2824-2 movements has effectively ended. Most new programs specify the SW200 instead.
Should a new collection use SW200-1 or SW200-2?
The -2 offers a much longer power reserve with the same external architecture. The trade-off is that its internal parts are not interchangeable with the -1, so spare-parts planning needs to account for the version actually shipped.
Can I switch from NH35 to Miyota 9015 without changing the case?
Generally no. Diameter, height, dial-feet positions and stem height differ, so the case and dial need to be engineered for the movement.
If you are specifying a movement for a new or existing collection and want a second opinion on what each option means for your case design, grade and schedule, talk to us about your project.