Osawalla Slim Core Smart Ring
Half the width, same sensors. For people who forget they’re wearing a ring.
$49.99Finish
Size
US sizes 6–13. Between sizes? We recommend sizing up.
Free sizing kit included ($0.00) — added to your order automatically. Try the sizes at home, confirm your size, then your ring ships. Your total stays $49.99.
Free standard shipping on all orders . 30-day returns on unused items.
- ✓The same 3× optical + 2× temperature array as Signature
- ✓Polished titanium, ~6 mm width
- ✓2.5–4 g — our lightest ring
- ✓No subscription — ever
Why the Slim
Less ring, same signal
Feather on your finger
At roughly six millimetres wide and as light as 2.5 grams, the Slim is the ring you put on in the morning and forget until the app reminds you it worked all night.
Nothing given up
The Slim carries the identical sensor array and app experience as the Signature — sleep staging, heart rate, SpO₂, HRV and 7-day battery included.
Polished to disappear
The high-polish finish reads like classic jewellery — at a glance it is a ring, not a gadget.
Compare
Which ring is right for you?
| Signature | Slim | Ceramic | |
|---|---|---|---|
| Material | Brushed titanium | Polished titanium | Ceramic |
| Width | 8 mm | ~6 mm | ~7 mm |
| Weight | 3–5 g | 2.5–4 g | 3–5 g |
| Battery | Up to 7 days | Up to 7 days | Up to 7 days |
| Sensors | 3× optical + 2× temperature | 3× optical + 2× temperature | 3× optical + 2× temperature |
| Sizes | US 6–13 | US 6–13 | US 6–13 |
| Best for | First-timers who want it all | Minimal feel | Scratch-proof style |
| Price | $49.99 | $49.99 | $49.99 |
In the box
Inside the box
- ✓Slim ring
- ✓Wireless charging case
- ✓USB-C cable
- ✓Quick start guide
Shipping, Warranty & Returns
Buy with confidence
Free standard shipping on all orders , dispatched from our US warehouse in 1–2 business days.
Every Osawalla product is covered for 12 months against manufacturing defects, handled through our support center.
Unused items in resalable condition can be returned within 30 days of delivery for a full refund.
Specifications
Osawalla Slim — full specification
| Materials | Polished titanium, scratch-resistant coating |
|---|---|
| Band width | ~6 mm |
| Weight | 2.5–4 g depending on size |
| Battery | Up to 7 days typical use |
| Subscription | None. All metrics and history included. |
| Water resistance | IP68 — splash, rain and hand washing. Not for swimming or diving. |
| Sensors | 3× optical (HR, SpO₂, HRV) + 2× temperature |
| Compatibility | iOS 12+ / Android 8.0+, Bluetooth 5.0 |
| Sizes | US 6–13 |
| In the box | Ring, charging case, USB-C cable, quick start guide |
FAQ
Frequently asked questions
Select “I don’t know my size” above and we ship you a free sizing kit first — you only confirm the size when the kit arrives. 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.
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.
Orders ship from our US warehouse. Standard delivery is 5–8 business days; expedited is 2–3. If you order with a sizing kit, the kit ships first and the ring follows after you confirm your size.
30 days from delivery. The item needs to be in a resalable condition; hygiene-sealed items such as sizer kits are excluded unless faulty.
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What buyers say
Health disclaimer
OSAWALLA devices are wellness products. They are not medical devices and are not intended to diagnose, treat, cure or prevent any disease. Heart rate, blood oxygen, HRV and sleep values are estimates for personal trend tracking only. Do not use them to make medical decisions. If you have a health concern, speak to a clinician.
Setup, pairing, charging and troubleshooting walkthroughs live in the support center.
Ring Size Guide
Osawalla ring sizes follow US ring sizing. To find your correct size, use our free sizing kit by following the steps below:
Select “I don’t know my size” and a free sizing kit is added at $0.00 — we send it before your smart ring ships.
Your sizing kit will arrive in 3–8 days (varies by location).
Choose your preferred finger for sizing. For optimal comfort and accuracy, we recommend the index, middle, or ring finger.
Go to “My Orders” to submit your size. If you don’t have an Osawalla account, sign up with the email you used to place your order.
For additional tips on finding your perfect ring size, check out our Size Guide.