Ultrahuman does not state that the Ring PRO measures SpO2. We checked four of the company's own pages — the Ring PRO product page, the buy page, the ring FAQ and the published field list for its Partner API — and none of them mentions SpO2, blood oxygen, oxygen saturation or pulse oximetry. That is not the same as a no. It means the manufacturer has not said.
The buy page lists the Ring PRO's sensors as “Temperature, redesigned PPG, 6-axis IMU”. A PPG sensor is what optical blood-oxygen estimation is built on, so the hardware may well be capable — but capability and a shipped metric are different things, and Ultrahuman names neither the metric nor the feature anywhere we could find.
The Partner API documentation is the most telling. Ultrahuman publishes the list of fields it returns: sleep data, movement data, steps, heart rate, HRV, temperature, VO2 Max, Recovery Index, Movement Index and Metabolic Score. No SpO2 field. If the ring produced a blood-oxygen number, that is where you would expect it to surface.
Search for this question and you will find pages attaching SpO2 to Ultrahuman — but read closely and most of them are about the *Ring AIR*, the earlier model. Inferring a Ring PRO spec from a Ring AIR page is exactly the mistake that puts wrong numbers into comparison tables and keeps them circulating for years. Two models from the same company with a redesigned sensor stack are two different products until the manufacturer says otherwise.
Plenty, and it is well documented: heart rate and resting heart rate, HRV, skin temperature, sleep stages broken into REM, deep and light, steps and workouts. Ultrahuman claims up to 15 days of battery, 3.3–4.8 g depending on size, titanium with a PVD coating, and 100 m water resistance. It also states there are no recurring subscription fees for accessing your data.
There is one asterisk on that last point. AFib detection exists as a PowerPlug — Ultrahuman describes it as monitoring your heart rhythm every night — but it is a paid add-on at $2.9 a month bundled with Cardio Adaptability, and Ultrahuman describes “medical approval in limited markets currently”, listing Europe, the UK, Turkey and Switzerland, with the USA, UAE and India as coming. So the ring itself has no subscription; one of its more interesting features does.
If overnight blood oxygen is the reason you are buying, do not buy on an inference. Ask Ultrahuman directly before ordering, and treat any third-party spec table that confidently prints a yes or a no as unverified. On our own comparison page this cell reads “Not stated” and lists the four pages we checked, precisely so the next person does not have to repeat the work.
For a ring that does document overnight SpO2, Oura states it measures blood oxygen while you sleep, needs a sleep period longer than three hours, and reports an average for the night — on Gen3 rings and newer, with an active Membership.
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