---
product_id: 688621561
title: "Oura Ring 4 - Black - Size 9 | Smart Ring Sizing Kit - Sleep Tracking, Heart Rate, Fitness Tracker, Up to 8 Days Battery Life"
brand: "oura"
price: "4465 Lei"
currency: RON
in_stock: true
reviews_count: 12
category: "Oura"
url: https://www.desertcart.ro/products/688621561-oura-ring-4-black-size-9-smart-ring-sizing-kit
store_origin: RO
region: Romania
---

# 8 days battery life 24/7 heart rate tracking detailed health analytics Oura Ring 4 - Black - Size 9 | Smart Ring Sizing Kit - Sleep Tracking, Heart Rate, Fitness Tracker, Up to 8 Days Battery Life

**Brand:** oura
**Price:** 4465 Lei
**Availability:** ✅ In Stock

## Summary

> 💍 Unlock your best self with the smartest ring on your finger.

## Quick Answers

- **What is this?** Oura Ring 4 - Black - Size 9 | Smart Ring Sizing Kit - Sleep Tracking, Heart Rate, Fitness Tracker, Up to 8 Days Battery Life by oura
- **How much does it cost?** 4465 Lei with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ro](https://www.desertcart.ro/products/688621561-oura-ring-4-black-size-9-smart-ring-sizing-kit)

## Best For

- oura enthusiasts

## Why This Product

- Trusted oura brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Power That Lasts:** Up to 8 days of battery life with fast, wireless charging—stay unplugged longer.
- • **Effortless All-Day Wear:** Sleek, lightweight design fits comfortably for continuous health insights.
- • **Deep Health Intelligence:** Monitors heart rate, sleep quality, and activity to optimize your wellness journey.
- • **Personalized Style & Fit:** Available in multiple finishes and sizes to match your unique lifestyle and look.
- • **Seamless Smartphone Sync:** Instant app updates keep your health data at your fingertips, anytime, anywhere.

## Overview

The Oura Ring 4 is a cutting-edge smart ring designed for professionals seeking discreet, continuous health monitoring. Featuring advanced heart rate, sleep, and activity tracking, it offers up to 8 days of battery life with wireless charging. Its sleek, comfortable design pairs with a powerful app for real-time insights, making it the ultimate wearable for optimizing wellness without sacrificing style.

## Description

Free delivery and returns on eligible orders. Buy Oura Ring 4 - Black - Size 9 | Smart Ring Sizing Kit - Sleep Tracking, Heart Rate, Fitness Tracker, Up to 8 Days Battery Life at desertcart UK.

Review: So So Happy! - 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.
Review: A great alternative to a smart-watch - 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.

## Features

- Compact and intelligent design for comfortable everyday wear
- Advanced health monitoring capabilities, including heart rate, sleep patterns, and activity tracking
- Long battery life with convenient wireless charging
- Seamless smartphone app integration for detailed health and activity analytics
- Available in multiple finishes and sizes for personalized style

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0D9WTFDBF |
| Batteries | 1 Lithium Polymer batteries required. (included) |
| Best Sellers Rank | 298 in Electronics & Photo ( See Top 100 in Electronics & Photo ) 1 in Wearable Tech Rings |
| Colour | Black |
| Connectivity technologies | Bluetooth |
| Customer Reviews | 4.3 4.3 out of 5 stars (5,849) |
| Date First Available | 3 Oct. 2024 |
| GPS | No GPS |
| Human interface input | Buttons |
| Item Weight | 181 g |
| Item model number | JZ90-54144-09 |
| OS | [Proprietary operating system] |
| Other display features | Wireless |
| Product Dimensions | 2.6 x 2.6 x 0.7 cm; 181 g |
| Special features | Heart Rate Monitor, Activity Tracker |
| What’s in the box | Information Booklet, Oura Ring 4, Oura Ring 4 Charger, Quick Start Guide, USB-C Cable |

## Product Details

- **Battery capacity:** 7000 Milliamp Hours
- **Battery cell composition:** Lithium Polymer
- **Brand:** OURA
- **Connectivity technology:** Bluetooth
- **GPS:** No GPS
- **Model name:** JZ90-54144-09
- **Operating system:** [Proprietary operating system]
- **Shape:** Round
- **Special feature:** Heart Rate Monitor, Activity Tracker
- **Wireless communication standard:** Bluetooth

## Images

![Oura Ring 4 - Black - Size 9 | Smart Ring Sizing Kit - Sleep Tracking, Heart Rate, Fitness Tracker, Up to 8 Days Battery Life - Image 1](https://m.media-amazon.com/images/I/513EeiCr+QL.jpg)
![Oura Ring 4 - Black - Size 9 | Smart Ring Sizing Kit - Sleep Tracking, Heart Rate, Fitness Tracker, Up to 8 Days Battery Life - Image 2](https://m.media-amazon.com/images/I/51f7Md52AIL.jpg)
![Oura Ring 4 - Black - Size 9 | Smart Ring Sizing Kit - Sleep Tracking, Heart Rate, Fitness Tracker, Up to 8 Days Battery Life - Image 3](https://m.media-amazon.com/images/I/71jVxf3HxrL.jpg)
![Oura Ring 4 - Black - Size 9 | Smart Ring Sizing Kit - Sleep Tracking, Heart Rate, Fitness Tracker, Up to 8 Days Battery Life - Image 4](https://m.media-amazon.com/images/I/613EYvr-lAL.jpg)
![Oura Ring 4 - Black - Size 9 | Smart Ring Sizing Kit - Sleep Tracking, Heart Rate, Fitness Tracker, Up to 8 Days Battery Life - Image 5](https://m.media-amazon.com/images/I/61FFomT0clL.jpg)

## Available Options

This product comes in different **Color, Size** options.

## Questions & Answers

**Q: How long should my ring work between charges?**
A: Oura Ring 4 typically lasts 5-8 days on a full charge, depending on usage. Contact Oura Member Care if you have questions or concerns with battery life, and they will ensure your problem is resolved

**Q: How do I choose the right Oura Ring size?**
A: Using the Oura Ring 4 Sizing Kit, choose a finger for your ring. We recommend the index, middle or ring finger. Wear the sizer ring for 24 hours to ensure the fit is secure and comfortable over the course of your day.

**Q: What's included?**
A: Oura Ring 4, Oura Ring 4 Charger, and USB-C Cable.

**Q: How do I see my Oura Ring metrics?**
A: After activating your Oura Ring, you can choose a monthly or annual membership to unlock full access to Oura’s features, daily health and wellness metrics, and personalized guidance.

**Q: Can I use more than one ring?**
A: Oura Members can now connect more than one Oura Ring 4 to their Oura App and quickly switch between them. Note, this feature only supports wearing and syncing data from one active Oura Ring at a time.

## Customer Reviews

### ⭐⭐⭐⭐⭐ So So Happy!
*by M***D on 18 October 2025*

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.

### ⭐⭐⭐⭐⭐ A great alternative to a smart-watch
*by S***Y on 16 June 2025*

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.

### ⭐⭐⭐⭐⭐ A great tool which does exactly what it says.
*by T***P on 12 December 2025*

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.

## Frequently Bought Together

- Oura Ring 4 - Black - Size 9 - Smart Ring - Size First with Oura Ring 4 Sizing Kit - Sleep Tracking Wearable - Heart Rate - Fitness Tracker - Up to 8 Days of Battery Life
- sylacor Ring Cover for Oura Ring Gen 4/ Gen 3, Anti-Scratch Elastic Silicone Oura Ring Case Protector for Men Women Working Out Gym

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*Product available on Desertcart Romania*
*Store origin: RO*
*Last updated: 2026-03-02*