Movements
Sellita SW300-1 vs ETA 2892
Wren has shipped both. Every Diver 38 delivered so far runs the ETA 2892-A2; watches shipping after August 2026 run the Sellita SW300-1. Since we have had both on the bench, here is a straight comparison rather than a marketing one.
The specifications
| ETA 2892-A2 | Sellita SW300-1 | |
|---|---|---|
| Diameter | 25.6mm (11½ ligne) | 25.6mm (11½ ligne) |
| Thickness | 3.6mm | 3.6mm |
| Frequency | 28,800 vph (4 Hz) | 28,800 vph (4 Hz) |
| Jewels | 21 | 25 |
| Power reserve | About 42 hours | 42 hours, or 56 with the current barrel |
| Winding | Automatic, bidirectional | Automatic, bidirectional |
Wren uses the 56-hour version.
What is genuinely the same
The SW300-1 is a clone of the 2892-A2, and not in a loose sense — it is dimensionally identical. Same diameter, same height, same stem position, same hand sizes. A case and dial designed around one will take the other without modification. That is the entire reason a swap like ours is possible without redesigning the watch.
Both run at 4 Hz, both wind in both directions, and both are thin. At 3.6mm the 2892 has been the default choice for slim automatics for decades, which is exactly why Sellita built an equivalent.
What actually differs
Jewel count. The SW300-1 has 25 jewels against the 2892’s 21. Four extra jewels is not a performance claim — jewel count is a poor proxy for quality — but it reflects Sellita’s own construction rather than a straight copy.
Power reserve. This is the meaningful one. Both movements historically ran about 42 hours. Sellita introduced an optimised barrel that lifts the SW300-1 to 56 hours, and that is the version in current Wren production. In practice it is the difference between taking the watch off on Friday evening and finding it stopped on Sunday, or finding it still running.
Origin and supply. Sellita built its business supplying components to ETA, then began producing complete movements when ETA restricted sales to outside brands. It has sourced independently of the Swatch Group since 2008. Both movements are Swiss made.
Refinement. The SW300-1 is a revision of the original SW300, with an updated gear tooth profile.
So which is better?
Neither, in any way you would feel on the wrist — with one exception. They keep time to the same standard, occupy the same space and are regulated the same way. The 56-hour barrel is a real, practical advantage, and it is the reason we did not treat the change as a downgrade to be apologised for.
The 2892 carries more romance. It has been in serious watches for forty years and people know the name. That is worth something, and we are not going to pretend otherwise.
Servicing
Both are standard Swiss calibres. Any competent watchmaker can service either, parts are widely available, and neither requires returning the watch to us or waiting on a proprietary component. That is deliberate: a watch you cannot get serviced in twenty years is not really yours.
Which one is in your Wren
- Diver 38 — ETA 2892-A2 on everything delivered to date; Sellita SW300-1, 56-hour version, on watches shipping after August 2026
- Diver One — Sellita SW200
- Diver One Titanium — ETA 2824
Every Wren has a display caseback, so you can see the movement. Full specifications for each model are on the watches page.
If you are unsure which you have, email us with your order number. More detail on the change is in the FAQ.