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Smart ring

Oura Ring 4

Silver finish, plus Oura Membership billed separately

$349US price, checked Oct 13, 2026

Oura's previous-generation smart ring, with the membership billed separately

Check price at Oura Full review →

Smart ring

Samsung Galaxy Ring

Titanium Black, sizes 5 to 15 (Titanium Silver and Titanium Gold also listed)

$399.99US price, checked Oct 13, 2026

Titanium sleep ring with no listed subscription, for Samsung Galaxy phone owners

Check price at Samsung Full review →

Our no-membership ring pick

Ultrahuman Ring PRO

Aster Black finish, whole sizes 5 to 14, with PRO Charging Case

$479US price, checked Oct 13, 2026

Subscription-free titanium ring with its charging case included

Check price at Ultrahuman Full review →

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Criterion	Oura Ring 4	Samsung Galaxy Ring	Ultrahuman Ring PRO
US price	$349Checked Oct 13, 2026 · Price details in the review	$399.99Checked Oct 13, 2026 · Price details in the review	$479Checked Oct 13, 2026 · Price details in the review
Three-year ownership estimate	$558.97 Incomplete known subtotal. Not included: energy use.	$399.99 Incomplete known subtotal. Not included: energy use.	$479 Incomplete known subtotal. Not included: energy use.
Choose if	You want Oura's sleep, heart-rate and temperature-trend tracking in the previous-generation ring and don't need Ring 5's smaller size.	You have a Samsung Galaxy phone and want sleep, heart-rate and skin-temperature tracking from a ring, without a monthly membership.	Anyone in a whole ring size from 5 to 14 who wants long battery life and would rather pay $479 once than pay a yearly membership.
Main trade-off	You pay a yearly membership for full features, and Oura says Ring 5 is 40% smaller with greater accuracy and battery power.	Samsung says it needs a compatible Samsung phone, and the ring page gives no weight, warranty, return terms or accuracy figures.	Ultrahuman publishes no Ring PRO accuracy figures on the pages checked, some features are paid PowerPlugs, and theft and loss cover needs the $54 two-year UltrahumanX plan.
Key specifications	Battery life: 5 to 8 days. A charge typically takes 20 to 80 minutes, depending on battery level. Oura says battery life and longevity depend on ring size, app settings and feature configuration Sensors: Red and infrared LEDs for blood oxygen. Green and infrared LEDs for heart rate, heart rate variability and respiration rate. A digital temperature sensor and an accelerometer Membership: $5.99 a month or $69.99 a year in the US, before tax. New members get the first month free. The ring has limited functionality without it Water resistance: Up to 100 m (328 ft) Compatibility: iOS and Android Connectivity: Bluetooth Low Energy, with airplane mode support. Firmware updates come through the Oura App. Oura lists the ring as FCC-certified Weight: 3.3 to 5.2 g depending on size	Battery life: Up to 7 days for sizes 12 and 13, and up to 6 days for smaller sizes. Samsung says that, 'combined with a full cradle charge,' you can use the ring for up to 14 days without plugging into an outlet. Battery life isn't stated for sizes 14 and 15 Sensors: Accelerometer, optical bio-signal sensor and skin temperature sensor Subscription: None listed on Samsung's Galaxy Ring page Compatibility: Samsung's US page says the ring requires a compatible Samsung phone, the Samsung Health app and a Samsung account. The account must be registered on a Samsung Galaxy smartphone. The page doesn't mention other Android phones, iPhone or a minimum software version. Energy Score needs a compatible Samsung Galaxy AI phone, and select Galaxy AI features need a compatible Samsung Galaxy phone. Snore detection needs Samsung Health 6.22 or later, with the phone within 2 feet Water resistance: 10ATM (up to 100 m for up to 10 minutes) and IP68 (up to 6 feet for up to 30 minutes). Samsung says to rinse and dry the ring after it gets wet Tracking features: Sleep score, sleep stages, snore detection, skin temperature during sleep, heart rate with high heart rate alerts, Energy Score, cycle tracking powered by Natural Cycles, steps, and automatic walking and running detection (you turn it on in Settings) Sizes and colors: Sizes 5 to 15 on the buy page, some shown as out of stock. The ring page says the range now includes two new sizes but doesn't name them. Titanium Black, Titanium Silver and Titanium Gold, with Gold shown as out of stock. The sizing kit's sample rings cover 9 sizes, from 5 to 13	Battery life: Up to 15 days (about 12 days in Turbo Mode, 15+ days in Chill Mode). Up to 45 days between wall charges with the PRO Charging Case. About 2.5 hours for a full charge. Sensors: Temperature sensor, redesigned PPG sensor and 6-axis IMU. Dual-core processor with on-chip machine learning. Subscription: No recurring subscription fees for accessing your data. Optional PowerPlugs cost extra. Cardio Adaptability, for example, is $24 for 1 year or $38 for 2 years. Cycle & Ovulation Pro is $39 for 1 year or $69 for 2 years. Data storage: Up to 250 days of data on internal and external flash, per Ultrahuman's comparison page. Up to 1 year of ring data backed up to the PRO Charging Case. Water resistance: 100 m (328 ft) Sizes: 5 to 14, no half sizes. Ultrahuman says its sizes may differ slightly from standard US ring sizes. Weight and thickness: 3.3 to 4.8 g depending on size. 2.65 mm thick (varies by size).
Exact variant	Silver finish, plus Oura Membership billed separately	Titanium Black, sizes 5 to 15 (Titanium Silver and Titanium Gold also listed)	Aster Black finish, whole sizes 5 to 14, with PRO Charging Case
Dimensions	7.90 mm wide and 2.88 mm thick. It weighs 3.3 to 5.2 g, depending on ring size.	Not stated by the manufacturer. The Galaxy Ring page describes an 'elegant, lightweight design' but gives no weight, width or thickness.	It's 2.65 mm thick, though thickness varies by size. It weighs 3.3 to 4.8 g depending on size. Ultrahuman doesn't state band width or per-size inner diameter on the pages checked.
Installation	No installation. It pairs with the Oura app on iOS or Android. It charges on the included size-specific charger with a USB-C cable. Oura offers a free sizing kit with plastic sizers before you order.	No installation. Samsung says you need a compatible Samsung phone, the Samsung Health app and a Samsung account. Health data is stored in the Samsung Cloud connected to your account. The ring charges in the Galaxy Ring Charging Case, which has a clear cover and LED lights that show charging progress. The pages checked didn't list what's in the box. The buy page offers a free sizing kit, and the ring page says its sample rings come in 9 sizes, from 5 to 13. The kit ships to your home. You wear a sample ring for at least 24 hours, then confirm your size on the 'My Order' page.	No installation. It pairs over Bluetooth (BLE 5.3) with the Ultrahuman app, which is on the App Store and Google Play. In the box are the ring, the Ring PRO Charger and a 1 m USB-C to USB-C cable. Ring PRO charges only on the PRO Charger or PRO Charging Case, not on a Ring AIR charger. Before you order, Ultrahuman offers a free sizing kit with plastic sizers in sizes 5 to 14.
Materials	The inner and outer surfaces are titanium, and the interior has no seams. Oura says minor scratches from regular wear are normal.	Titanium, in three scratch-resistant finishes. Samsung says the concave design minimizes scratches. It describes Titanium Black and Titanium Silver as 'matted'.	The ring is titanium with a PVD coating, plus epoxy and polycarbonate. Ultrahuman says the inner surface is hypoallergenic plastic and titanium. The charging case is aluminum, stainless steel and plastic.
Warranty	A 1-year protection plan is included with purchase. The product page offers upgrades to 2 years for $45 or 3 years for $60.	Not stated by the manufacturer on the Galaxy Ring page. The page links to Samsung's general 'Warranty Information' page without giving terms.	A 12-month limited warranty runs from delivery and covers defects in materials and workmanship. It's valid only in the country of purchase. The Terms of Sale, which don't name Ring PRO, exclude consumable parts such as batteries or protective coatings unless a defect caused the failure. They also exclude accidents, misuse and normal wear and tear. Cosmetic damage such as scratches and dents isn't covered unless a defect caused it. Upgrading through trade-in resets the warranty. Optional UltrahumanX coverage costs $36 for 1 year, with accidental damage protection and priority care. The $54 plan for 2 years adds theft and loss protection and what Ultrahuman calls weight loss insurance.
Returns	If you bought the ring directly from Oura's online store, you can return it within 30 days of receiving the order. It has to be fully functional and undamaged, and come back with the charger and USB-C cable. Ring sets can't be partly returned. Exchanges are only for a different size of the same ring, and each item can be returned or exchanged once. Refunds go to the original payment method, but original shipping and handling aren't refunded. Rings bought from other retailers follow that retailer's policy. Oura's return FAQ says to cancel the membership when you return a ring. The Ring 4 Silver product page says canceling doesn't entitle you to a full or pro-rated refund of fees you've paid. Warranty replacements can't be returned for a refund.	Not stated by the manufacturer on the Galaxy Ring page. The page links to Samsung's general 'Returns' page in its footer without giving terms.	If you're not completely satisfied, you can return it within 30 days of delivery. Send it back in the original packaging with all original accessories, including the charger. The Ring PRO FAQ and the Smart Rings Terms of Sale both say return shipping is free. No restocking fee is stated. The Terms of Sale list these return terms under the Ring AIR heading, and the FAQ applies them to Ring PRO.
Unresolved questions	Who pays return shipping, which Oura's return FAQ doesn't say How long Oura will keep selling and supporting Ring 4 now that Ring 5 is on sale How accurately Ring 4 itself stages sleep against polysomnography Battery lifespan, out-of-warranty replacement cost and charging power draw The FDA regulatory status of Ring 4 features, which the pages checked didn't confirm	Whether your size and color checks out at $299.99 or $399.99 Whether $299.99 is a temporary discount Weight, band width and thickness Warranty length and return window: the ring page links to Samsung's general warranty and returns pages without stating terms Battery life for sizes 14 and 15 Whether a sizing kit is offered for sizes 14 and 15 How accurate Galaxy Ring is against polysomnography or ECG, since no independent, peer-reviewed data was reviewed for this review Battery lifespan, out-of-warranty repair cost and charger power draw Which Samsung phones and software versions count as compatible Whether other Android phones work: Samsung's US page mentions only Galaxy phones, and news reports found in a search suggest they may, though those reports weren't reviewed here Which feature Samsung's 'Must wear device for 7 nights during a 30 night period' footnote applies to How long Samsung will keep selling and supporting the ring (no Galaxy Ring 2 was listed on the page checked)	Band width and per-size inner diameter Whether a worn-out battery is repaired or replaced at a cost, since the Terms of Sale exclude battery wear from the limited warranty Independent, peer-reviewed accuracy data for Ring PRO against polysomnography or ECG Battery lifespan, out-of-warranty replacement cost and charger power draw Renewal prices for PowerPlugs after the first term Minimum supported iOS and Android versions How long Ultrahuman will sell and support Ring PRO in the US

These comparisons use published specifications, not head-to-head tests. Prices and terms are dated. Unknown costs are not zero. Check the exact variant before you buy.