SR-40 – SR-59
Ceramic series
Ceramic replaces the brushed metal outer shell with a polished ceramic layer. It is cooler to the touch, does not pick up fingerprints, and holds a deep gloss.
Who it is for: For people who want the ring to read as jewellery first.
- Polished ceramic shell
- Titanium inner core
- IP68
- US 6–13
Ceramic is not on sale yet. The polished ceramic shell is in tooling. The Signature and Slim series use the same sensor array and are available now.
Side by side
Compare every Ceramic model
Same sensor array, different shape — or different job entirely.
| Signature | Slim | |
|---|---|---|
| Band | Closed titanium, full width | Closed titanium, narrow |
| Sensors | 3 optical + 2 temperature | 3 optical + 2 temperature |
| Battery | Up to 7 days | Up to 7 days |
| Sizes | US 6–13 | US 6–13 |
| Best for | US 8 and above | US 7 and below, or if you dislike a wide band |
| Subscription | None | None |
Fit & lens
Before you order
Size & fit
- ·Available in US sizes 6–13. Not sure? Choose “I don’t know my size” for a free sizer kit — the fit decides data quality.
- ·Index, middle or ring finger. Measure the exact finger you will wear it on.
- ·Titanium with a scratch-resistant coating; 3–5 g depending on size.
- ·IP68 covers rain, splashes and hand washing. It is not rated for swimming.
Fit decides whether the data is any good
A smart ring reads through the base of the finger. Too loose and the signal drops out overnight; too tight and you will not keep it on. Measure the exact finger you plan to wear it on, then wear the sizer for a full day and night.
FAQ
Ceramic questions we get most
Not sure of your size? Choose “I don’t know my size” and a free sizer kit ships first. A smart ring needs a snug fit because the sensors read through the base of the finger — a loose ring gives you a worse signal, not a more comfortable one. Wear your candidate size for a full day and night before deciding.
No. Every metric, every history view and every trend is included with the ring. There is no premium tier.
Index, middle or ring finger. The important thing is that you measure the exact finger you plan to use — the same size number is a different fit on different fingers.
The ring is IP68 rated, which covers rain, hand washing and splashes. It is not rated for swimming or diving, and we do not recommend wearing it in a pool or the sea.