OURA Ring 4 – Black – Size 15 – Smart Ring | Size First Ring 4 Sizing Kit | Sleep Tracking Wearable – Heart Rate – Fitness Tracker – Up to 8 Days Battery Life
The OURA Ring 4 is the ultimate black smart ring and minimalist wearable fitness tracker (Size 15), engineered for comprehensive well-being and health monitoring. This sleek device provides world-class accurate Sleep Tracking, Heart Rate Monitoring, and Fitness Tracking, delivering actionable recovery insights directly to you. Enjoy reliable, uninterrupted data collection with an exceptional battery life of up to 8 days per charge, with the included Size First Ring 4 Sizing Kit ensuring your perfect fit.
- Advanced Sleep Analysis: Clinical-grade accuracy tracking REM, deep, and light sleep stages.
- 24/7 Heart Rate and HRV Monitoring for continuous health and readiness insights.
- Up to 8 Days Battery Life for reliable, long-term tracking without frequent charging.
- Durable, Lightweight Design with seamless Bluetooth connectivity to the OURA app.
£439.74 Original price was: £439.74.£313.74Current price is: £313.74.
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Description
Product Overview
Transform your health tracking with the OURA Ring 4 in Black (Size 15), the ultimate smart ring and minimalist fitness wearable designed for comprehensive well-being. This sleek, non-intrusive tracker provides world-class accuracy in Sleep Tracking, Heart Rate Monitoring, and overall Fitness Tracking, all condensed into a comfortable ring design. With an exceptional up to 8 Days of Battery Life, the OURA Ring 4 provides uninterrupted data collection, giving you deep, actionable insights into your recovery, readiness, and daily activity. Your purchase includes the Size First Ring 4 Sizing Kit to ensure the perfect fit for maximum data precision. Upgrade to the future of wearable technology—get instant feedback on your body’s signals and optimize every part of your day, from deep sleep to high-intensity workouts.
Key Features
- Advanced Sleep Analysis: Tracks REM, deep, and light sleep stages with clinical-grade accuracy.
- 24/7 Heart Rate Monitoring: Continuous and precise heart rate and HRV (Heart Rate Variability) tracking.
- Exceptional Battery Life: Enjoy up to 8 days of power on a single charge for reliable, long-term tracking.
- Activity and Fitness Tracker: Measures steps, calories burned, and monitors daily movement goals.
- Seamless Bluetooth Connectivity: Integrates effortlessly with the OURA smartphone app for detailed analytics.
- Durable & Lightweight: Constructed from a premium, comfortable material suitable for continuous wear.
Important Information
- Product is OURA Ring 4, Black, Size 15.
- Includes the Size First Ring 4 Sizing Kit to confirm optimal fit.
- Requires the OURA smartphone application (iOS/Android compatible).
- Features Lithium Polymer battery composition.
- Style is Minimalist/Ring Shape.
Why Choose Think Assemble
- Quality Assurance: Every OURA Ring is verified for authenticity and top performance.
- Fast & Secure Shipping: Get your powerful fitness tracker quickly and reliably.
- Dedicated Support: Access expert customer service ready to assist with setup and use.
- Hassle-Free Returns: Shop with confidence knowing your satisfaction is guaranteed.
Specification
Overview
| Weight | 191 g |
|---|---|
| Dimensions | 2.4 × 2.4 × 0.7 cm |
| Batteries |
1 Lithium Polymer batteries required. (included) |
| Product Dimensions |
2.4 x 2.4 x 0.7 cm; 191 g |
| Date First Available |
3 Oct. 2024 |
| Manufacturer |
Oura |
| Item model number |
JZ90-54144-15 |
| Country of origin |
Estonia |
Customer Reviews
22 reviews for OURA Ring 4 – Black – Size 15 – Smart Ring | Size First Ring 4 Sizing Kit | Sleep Tracking Wearable – Heart Rate – Fitness Tracker – Up to 8 Days Battery Life
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Laura de la Garza –
Amazing! The price was excellent, the quality is great, it tracks my sleep, my meals, my daily activity and it looks elegant and sleek. You can wear it for days and the battery lasts a lot. The best Christmas present!
Miss Chansigaud –
I hesitated for a while before investing in this gadget. And I love my Gadgets! but after doing some homework on the competition, I decided to jump for it.First, the fit and metal colour are great, I couldn’t be happier, the quality and durability is insane, i do everything with it, I rarely take it off.The connectivity to my Samsung Z Fold6 was flawless, no hiccups, plus, everything you open the app, it updates in no time. so great compatibility.Now, you need to give it time to gather data about you, of course… it will not happen overnight which is quite right, but the intel you get afterwards is great.Your body age, sleep quality, energy available, your stress, it is such a great little ring. it is a lot of money for such a small device but the value for money is worth it.I highly recommend it if you are curious and want to be nudge in the right direction for better health.
Snowy –
I was keen to utilise technology to help with my fitness, but love mechanical watches so a smart-watch wasn’t an option. Came across this and after some research I gave it a punt. Very happy customer, the ring is a doddle to set up and works a treat. Battery life is a snadge less than advertised but not enough to make me dock points.It’s a shame about the subscription, as I think the ring is costly enough that it’s something of a liberty to charge for ongoing use, they could lose things like the guided meditation etc and give a free option, or bake in more value-add to the app.Enough moaning though, what it does it does really well, giving me insights into my sleep patterns and broader health. I am happy I bought it and check the app at least daily months after buying.
Tim Framp –
The app is brilliant.It takes a while to get to know you, so don’t expect instant insights, but as it builds a picture it is really good at telling you what’s going on. I am using it to track my food etc as well, so not exclusively related to what’s happening on the ring.On the ring specifically?Well, it is chunkier than a ring you’d buy as jewellery. That’s ok and it’s not ridiculous, but you have to get used to it. I do find I take it off and put it on more, or change fingers, as my hand needs a rest.The colour… Despite the name stealth, does stand out. If you want something more subtle then brushed or silver is probably better, as it’s more like typical jewellery. That being said, I’ve gotten used to it.Sizing – definitely get the sizing kit and wear not for a few mins but for a day or two to understand how your fingers change size.Battery life is good. I reckon 8 charge it once every 4 otlr 5 days so far. I understand turning off blood oxygen measuring is the way to really eek out more battery life. You can also use airplane mode to reduce how often it speaks to your phone.But yeah, no regrets, it’s a great tool and honestly, easier to live with than a smart watch.
T Mac –
I have used this product and it is genuinely excellent. The quality is great, it works exactly as described, and it is something I was happy to reorder (hopefully I shouldn’t have to). The item itself deserves praise and I would recommend it based on performance and reliability.However, the service around this order was extremely poor and it affected the entire experience. My delivery was scheduled for 24 November 2025 between 11am and 2pm. When 2pm arrived, the delivery window changed to 2:30pm. When 2:30pm passed, there was still no delivery. Much later in the evening thinkassemble.co.uk attempted to deliver at 7:22pm even though my delivery preferences clearly stated delivery only up to 6pm.Although this review focuses on how good the product is, I feel that mentioning the delivery problems is important because they continue to happen and they create a real bottleneck for thinkassemble.co.uk. It was unreliable, frustrating and completely unnecessary.To make things worse, thinkassemble.co.uk deleted my original review and told me to edit it, even though they had already removed it and there was no record for me to update. Thankfully I expected this might happen so I kept a copy and can rewrite my honest experience here.In the end I cancelled the order and bought the same item from John Lewis, who usually provide a smoother and more respectful service. The product remains excellent, but the delivery experience and the handling of my review by thinkassemble.co.uk were very disappointing.
Marco –
Tracks biometrics pretty accurately. Has a premium price plus a subscription. Add to the fact that they scratch quite easily it’s not a 5 star. Comfortable to wear, much more comfortable than a watch
Emma –
Oura Ring 4
Ich nutze den Oura Ring 4 nun seit einigen Wochen und bin rundum zufrieden. Die Verarbeitung ist hochwertig, der Tragekomfort hervorragend – selbst nachts stört der Ring überhaupt nicht. Die Messwerte zu Schlaf, Aktivität und Erholung sind erstaunlich präzise und helfen mir, meinen Alltag bewusster zu gestalten. Besonders die neuen Funktionen zur Hauttemperatur und Stressanalyse finde ich sehr gelungen. Wer eine unauffällige, aber leistungsstarke Alternative zu einer Smartwatch sucht, ist hier genau richtig.
Lucas –
使用して2週間で生活必需品です。
事前にサイズキットを購入して1,2日候補となる指でつけて生活することはマストです。Ouraリングそのものはデータが好きな人間にとって最高のツールです。結構厚みもありますが、日常生活で邪魔に感じることはほとんどなく日常の一部になっています。
Ula –
Najlepszy
Najlepszy tracker samopoczucia i dobrostanu
Tatiana Vela –
Padrísimo…
Increíble gran compra …
Inata Uchiwa –
Bien
Je ne l’ai pas depuis longtemps, mais pour l’instant j’en suis très satisfaite.Grâce au baguier, j’ai pu définir la bonne taille de bague. Je ne dirais pas qu’elle est rose, je dirais plus que ça fait métal doré mais joli. Et puis par rapport aux autres bagues connectées qui sont souvent noires, celle-ci est de fait, plus discrète. Je préfère.Quant aux fonctionnalités, avec l’application je suis mon sommeil, ma FC, la variabilité de ma FC, ma FR… J’ai découvert avec joie que mon âge cardiovasculaire est de 6 ans plus jeune que mon âge physiologique. Déjà que ma balance impédencemètre me dit que mon âge métabolique est de plus de 10 ans de moins que mon âge physiologique… Ces appareils sont très sympas!
Laura de la Garza –
Amazing! The price was excellent, the quality is great, it tracks my sleep, my meals, my daily activity and it looks elegant and sleek. You can wear it for days and the battery lasts a lot. The best Christmas present!
Miss Chansigaud –
I hesitated for a while before investing in this gadget. And I love my Gadgets! but after doing some homework on the competition, I decided to jump for it.First, the fit and metal colour are great, I couldn’t be happier, the quality and durability is insane, i do everything with it, I rarely take it off.The connectivity to my Samsung Z Fold6 was flawless, no hiccups, plus, everything you open the app, it updates in no time. so great compatibility.Now, you need to give it time to gather data about you, of course… it will not happen overnight which is quite right, but the intel you get afterwards is great.Your body age, sleep quality, energy available, your stress, it is such a great little ring. it is a lot of money for such a small device but the value for money is worth it.I highly recommend it if you are curious and want to be nudge in the right direction for better health.
Snowy –
I was keen to utilise technology to help with my fitness, but love mechanical watches so a smart-watch wasn’t an option. Came across this and after some research I gave it a punt. Very happy customer, the ring is a doddle to set up and works a treat. Battery life is a snadge less than advertised but not enough to make me dock points.It’s a shame about the subscription, as I think the ring is costly enough that it’s something of a liberty to charge for ongoing use, they could lose things like the guided meditation etc and give a free option, or bake in more value-add to the app.Enough moaning though, what it does it does really well, giving me insights into my sleep patterns and broader health. I am happy I bought it and check the app at least daily months after buying.
Tim Framp –
The app is brilliant.It takes a while to get to know you, so don’t expect instant insights, but as it builds a picture it is really good at telling you what’s going on. I am using it to track my food etc as well, so not exclusively related to what’s happening on the ring.On the ring specifically?Well, it is chunkier than a ring you’d buy as jewellery. That’s ok and it’s not ridiculous, but you have to get used to it. I do find I take it off and put it on more, or change fingers, as my hand needs a rest.The colour… Despite the name stealth, does stand out. If you want something more subtle then brushed or silver is probably better, as it’s more like typical jewellery. That being said, I’ve gotten used to it.Sizing – definitely get the sizing kit and wear not for a few mins but for a day or two to understand how your fingers change size.Battery life is good. I reckon 8 charge it once every 4 otlr 5 days so far. I understand turning off blood oxygen measuring is the way to really eek out more battery life. You can also use airplane mode to reduce how often it speaks to your phone.But yeah, no regrets, it’s a great tool and honestly, easier to live with than a smart watch.
T Mac –
I have used this product and it is genuinely excellent. The quality is great, it works exactly as described, and it is something I was happy to reorder (hopefully I shouldn’t have to). The item itself deserves praise and I would recommend it based on performance and reliability.However, the service around this order was extremely poor and it affected the entire experience. My delivery was scheduled for 24 November 2025 between 11am and 2pm. When 2pm arrived, the delivery window changed to 2:30pm. When 2:30pm passed, there was still no delivery. Much later in the evening thinkassemble.co.uk attempted to deliver at 7:22pm even though my delivery preferences clearly stated delivery only up to 6pm.Although this review focuses on how good the product is, I feel that mentioning the delivery problems is important because they continue to happen and they create a real bottleneck for thinkassemble.co.uk. It was unreliable, frustrating and completely unnecessary.To make things worse, thinkassemble.co.uk deleted my original review and told me to edit it, even though they had already removed it and there was no record for me to update. Thankfully I expected this might happen so I kept a copy and can rewrite my honest experience here.In the end I cancelled the order and bought the same item from John Lewis, who usually provide a smoother and more respectful service. The product remains excellent, but the delivery experience and the handling of my review by thinkassemble.co.uk were very disappointing.
Marco –
Tracks biometrics pretty accurately. Has a premium price plus a subscription. Add to the fact that they scratch quite easily it’s not a 5 star. Comfortable to wear, much more comfortable than a watch
Emma –
Oura Ring 4
Ich nutze den Oura Ring 4 nun seit einigen Wochen und bin rundum zufrieden. Die Verarbeitung ist hochwertig, der Tragekomfort hervorragend – selbst nachts stört der Ring überhaupt nicht. Die Messwerte zu Schlaf, Aktivität und Erholung sind erstaunlich präzise und helfen mir, meinen Alltag bewusster zu gestalten. Besonders die neuen Funktionen zur Hauttemperatur und Stressanalyse finde ich sehr gelungen. Wer eine unauffällige, aber leistungsstarke Alternative zu einer Smartwatch sucht, ist hier genau richtig.
Lucas –
使用して2週間で生活必需品です。
事前にサイズキットを購入して1,2日候補となる指でつけて生活することはマストです。Ouraリングそのものはデータが好きな人間にとって最高のツールです。結構厚みもありますが、日常生活で邪魔に感じることはほとんどなく日常の一部になっています。
Ula –
Najlepszy
Najlepszy tracker samopoczucia i dobrostanu