Your #1 Destination for Premium Refurbished Tech
Oura Ring 4 Smart Ring Size 13 Black Titanium JZ90-54144-13
Product Description
Overview
Oura Ring 4 in Black, Size 13, model JZ90-54144-13. All-titanium band with black PVD finish, Smart Sensing, continuous heart rate and HRV, overnight SpO2, skin-temperature trend, sleep staging, Readiness, and Activity in the Oura app. Battery is typically 5–8 days. Water resistant to 100 m / 10 ATM. Not for diving. Width 7.90 mm, thickness about 2.88 mm. Weight is 3.3–5.2 g depending on size. Includes the size-matched charging dock and USB-C cable. Important: full scores and insights require an active Oura Membership on the buyer’s own account. Membership is not included and does not transfer. Set up a new Oura account and remove this ring from any prior account before use. This ring is Size 13 and is not adjustable. Oura sizing does not match standard jewelry sizes. Confirm size 13 before purchase.
Key Features
- Smart Sensing: Multi-path optical sensing for heart rate, HRV, respiration, and overnight blood oxygen. Readings are viewed in the Oura app, not on the ring.
- Sleep, Readiness, and Activity: Overnight sleep staging plus daily Readiness and Activity scores. These views require an active Oura Membership.
- Heart Rate, HRV, SpO2, and Temperature: Green and infrared LEDs for heart rate and HRV. Red and infrared LEDs for overnight blood oxygen. Digital temperature sensor for skin-temperature trends. Accelerometer for movement.
- Battery and Water Resistance: Typically 5–8 days per charge. Charge time is about 20–80 minutes on the included size-matched dock. 10 ATM / 100 m. Suitable for shower and swim. Not for scuba or diving.
- Black Titanium: Titanium inner and outer band with black PVD coating. Recessed inner sensors. This is the titanium Black finish, not an Oura Ring 4 Ceramic color.
- Size 13, iOS and Android: Oura size 13 only. Bluetooth Low Energy to the Oura app on iOS or Android. No GPS and no cellular radio.
Specifications
| Device Type | Oura Ring 4 Smart Ring — Size 13 |
| Model | JZ90-54144-13 |
| Color | Black |
| Material | Titanium inner and outer, black PVD coating |
| Size | 13 — not adjustable, not a standard jewelry size |
| Dimensions | 7.90 mm wide, about 2.88 mm thick |
| Weight | 3.3–5.2 g depending on size |
| Sensors | Heart rate, HRV, respiration, overnight SpO2, skin-temperature trend, accelerometer |
| Subscription | Oura Membership required for full insights. Not included. Does not transfer. |
| Battery | Typically 5–8 days. Charge about 20–80 minutes on the included dock. |
| Water Resistance | 10 ATM / 100 m. Not for diving. |
| Connectivity | Bluetooth Low Energy. No screen, GPS, or cellular. |
| App | Oura app, iOS and Android |
Connectivity
- Bluetooth Low Energy
- Oura App — iOS and Android
- Charging dock and USB-C cable included
- 10 ATM / 100 m — not for diving
What's Included
- (1) Oura Ring 4 — Black, Size 13, JZ90-54144-13
- (1) Size-matched charging dock
- (1) USB-C charging cable
Does Not Include
- (1) Original box
- (1) Oura sizing kit
- (1) Oura Membership
Condition Specifics
Very Good Condition — This item has been tested by trained technicians and is fully functional. The device has been professionally refurbished to very good condition and may show light signs of wear from normal use, such as faint scratches or minor surface marks. These are cosmetic only and do not affect performance. Please see the description for a complete list of included items and accessories.
The photos shown are example images representing the typical condition of the model listed. The actual device may vary slightly in cosmetic condition but will match the same model, specifications, and functional condition described. All units are fully tested per our internal quality standards. This ring is Size 13 and is not adjustable. Full Oura insights require the buyer’s own membership. Membership is not included.
Having an Issue With Your Item?
Contact us first. Our US based support team can troubleshoot most problems quickly, including setup, connectivity, charging, and performance questions. Message us through eBay and we will respond within one business day.
Free Returns, Any Reason!
Not satisfied? We offer free 30 day returns on this item no matter the reason, and you will receive a prepaid label either way.
One Small Ask From Our Small Business
When you start a return, please choose the reason that accurately describes your situation. As a small business, we review every return reason to catch real product issues and fix them in order to provide our customers the highest quality product. Regardless of the return reason, your return is always free and our support team is always here to help.
Disclaimer
The photos shown in this listing are example images that represent the typical condition and appearance of the model listed. The actual device you receive may vary slightly in cosmetic condition but will match the same model, specifications, and functional condition described in the listing. All units are fully tested and verified according to our internal quality standards.
Note: All units are fully tested and verified according to our internal quality standards. We do not open devices during our inspection or refurbishment process, and no internal components (such as batteries, screens, hard drives, etc.) are replaced.
 |