REXQU O2Max Health Watch
$169.97
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✓ Free shipping✓ 30-day returns✓ Ships in 24–48h
Your Oxygen, On the Record.
O2Max is a pulse oximeter watch that keeps reading while you sleep, which is when it matters. The O2Max is a blood oxygen smartwatch built around one-tap SpO₂ spot checks and oxygen trends. It also includes on-demand wrist ECG, HRV reports, sleep and heart-rate trends, plus daily activity tracking in a classic round design. It is intended for personal wellness awareness, not medical diagnosis.
✓ Free shipping ✓ 30-day return window ✓ iPhone & Android support*
O2Max brings SpO₂, wrist ECG and everyday wellness trends together in a classic round design, with each reading best used as part of your own longer-term pattern.
Follow heart-rate trends and alerts, with HRV information charted in the companion app for personal stress-and-recovery awareness.
Review daily step counts and calorie estimates in the app, charted beside your heart-rate and sleep data. For fitness awareness, not clinical assessment.
Take on-demand SpO₂ spot checks and review oxygen trends in the companion app. Wrist readings can vary with fit, movement and other conditions.
A 380mAh battery covers days of tracking, and the magnetic charger snaps itself into place.
Review estimated light, deep and REM sleep stages alongside overnight heart-rate and SpO₂ trends.
Designed for everyday exposure such as rain and sweat. Follow the current care instructions and do not treat IP67 as a swimming rating.
Daily activity, rest and sleep can all change your heart-rate pattern. O2Max collects supported heart-rate and HRV data so you can compare your own trends over time rather than relying on a single reading.
Heart-rate variability describes the variation in timing between heartbeats. O2Max presents HRV information and a Lorentz-style plot in the app so you can compare your own wellness trends across days, workouts and rest periods.
For wellness tracking and awareness — not medical diagnosis.
O2Max records steps and calorie estimates through the day and charts them in the companion app, so an active week and a quiet one are easy to tell apart at a glance.
For general wellness and fitness awareness — not a medical device.
Start an ECG recording from the wrist when you want to capture your rhythm for personal awareness. The companion app can display the waveform and supported ECG-related information that you can save for your own records or discuss with a healthcare professional.
O2Max is not a clinical 12-lead ECG and does not diagnose arrhythmia, coronary disease or other heart conditions.
Wear O2Max overnight to review estimated light, deep and REM sleep stages alongside heart-rate and oxygen trends. The value is in comparing patterns over time, not treating a wearable sleep score as a diagnosis.
O2Max puts wrist-based blood-oxygen readings within easy reach. Take an on-demand SpO₂ spot check and compare overnight or day-to-day trends alongside your heart-rate and sleep data in the companion app.
Wrist SpO₂ readings can be affected by fit, motion, circulation, temperature and other factors. Do not use O2Max to diagnose low oxygen or decide whether to seek medical care.
O2Max reads body temperature on the watch and charts it in the companion app beside your blood-oxygen and heart-rate data, so a shift away from your usual baseline is easy to spot across a week.
For general wellness and fitness awareness — not a medical device.
O2Max includes SOS and fall-detection features designed to help reach a configured contact when the required setup and connection are available. Response depends on settings, paired-phone or network conditions, battery level and signal.
O2Max is not a medical-alert service and should not be your only emergency-contact method.
O2Max pairs a metal-alloy body and 1.55-inch round display with wellness sensors and app-connected trend tracking, so it can look like a traditional watch while still serving as a daily health-and-fitness companion.
| Feature | REXQU O2Max | What to Know |
|---|---|---|
| Blood oxygen (SpO₂) | ✓ Spot checks + trends | Wellness readings; wrist accuracy varies with conditions |
| On-wrist ECG | ✓ On demand | Consumer wellness ECG, not a clinical 12-lead ECG |
| HRV | ✓ App report + Lorentz-style plot | Best used for personal trend awareness |
| Heart-rate trends | ✓ Included | Alerts and background tracking depend on settings |
| Sleep | ✓ Estimated stages | For wellness trends, not sleep-disorder diagnosis |
| Daily activity | ✓ Steps and calories | Estimates for fitness awareness, not clinical measurement |
| SOS + fall detection | ✓ Feature available | Depends on setup, connection, battery and network conditions |
| Display | ✓ 1.55″ round display | Classic round-watch design |
| Water resistance | ✓ IP67 rated | Everyday water resistance; not presented as a swimming watch |
| Sports modes | Published 150+ modes | Availability can vary by app/watch software |
| Battery | Published 7–15 day range | Actual runtime varies with sensors, display and usage |
| REXQU subscription | No required monthly REXQU subscription | Check current companion-app requirements |
The strongest value comes from comparing your own trends over time rather than treating any one wrist reading as a diagnosis.
Take a blood-oxygen spot check and compare it with your own previous readings, while remembering that wrist readings can change with fit and movement.
Review overnight sleep, heart-rate and oxygen trends together in the app to see how your own pattern changes over time.
Choose a leather, silicone or metal-style strap when you want blood oxygen, ECG and daily trend tools without giving up a classic round-watch appearance.
Silicone for the gym, leather for dinner, steel for the office — every strap carries the identical sensor suite. Tap one to order it.
From clean analogue dials to bold health dashboards, the app’s face library restyles your O2Max in seconds — and a photo of your own makes it truly yours.
Use the O2Max as a wellness-trend tool and use our guides to understand the limits of wrist SpO₂ and consumer ECG readings.
Read our SpO₂ accuracy and skin-tone Health Guide for factors that can affect wrist oxygen readings.
See the ECG smartwatch buying guide and AFib Health Guide.
Browse ECG smartwatches or the broader health smartwatch collection.
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A receipt is on its way to your email. Your O2Max ships within 24–48 hours.
Try O2Max during the return window. If it is not the right fit, request a return within 30 days in accordance with our Returns & Refund Policy.
SpO2 from the wrist is one of the most misunderstood readings in wearables. Here is how it works and what it is worth.
A pulse oximeter shines red and infrared light through tissue and measures how much of each comes back. Oxygenated and deoxygenated blood absorb the two wavelengths differently, so the ratio gives an oxygen-saturation estimate. A clinical fingertip oximeter does the same thing through a fingertip, which is thinner and better supplied with blood than a wrist — which is exactly why wrist readings are the less accurate of the two.
A loose strap, cold hands, poor circulation, tattoos and any movement during the reading will all shift the result. If a reading looks wrong, take another sitting still with the watch snug and your hand warm. Most alarming SpO2 readings are measurement artefacts rather than anything about you.
What a wrist device is genuinely good for is showing your own overnight pattern night after night — something a spot check can never do. A single low figure from a wrist sensor is not a reason to worry; a consistent change in your own pattern is worth mentioning to a clinician.
If you have been told to monitor your oxygen saturation for a health reason, use the device you were told to use. The FDA safety communication on pulse oximeter accuracy and limitations explains the limits of even clinical devices — including that accuracy can vary with skin pigmentation — and consumer wrist sensors are less accurate again.
Optical heart-rate tracking is the mature measurement here and worth more day to day. The American Heart Association target heart rate guide gives the ranges, and the CDC activity guidelines the weekly targets. IP67 covers rain and hand-washing, not swimming.
More from the range: all health smartwatches · ECG smartwatches · blood pressure smartwatches · daily health monitoring. Health statements follow our editorial and research standards.
Less accurate, and it is worth being clear about why. A fingertip oximeter reads through a thin, well-perfused fingertip; a watch reads through the wrist, where there is more tissue and less blood flow. Cold hands, a loose strap and movement degrade the wrist reading further. Use the watch for your own overnight and day-to-day trend, which a fingertip device cannot give you, and use a proper oximeter if you have been told to monitor oxygen saturation for a medical reason.
Almost always measurement conditions rather than your body. Cold hands, poor circulation, a loose strap, moving during the reading, or the watch sitting too far down the wrist all reduce the signal the sensor receives and push the estimate down. Warm your hands, sit still, tighten the strap a notch, and take another reading. Persistent changes in your own overnight pattern are what would be worth mentioning to a clinician — one odd figure is not.
O2Max combines wrist-based blood-oxygen spot checks, on-demand ECG, HRV information and broader wellness trends in a classic round smartwatch. Its health readings are for personal awareness rather than medical diagnosis.
Wrist SpO₂ readings can vary with watch fit, motion, circulation, skin characteristics, temperature and other conditions. Use O2Max to follow personal trends, not to diagnose low oxygen or replace a medical pulse oximeter.
No. O2Max can record a consumer wrist ECG and show supported app-based rhythm information, but it is not a clinical 12-lead ECG and does not diagnose arrhythmia, coronary disease or other heart conditions.
Yes. O2Max records daily step counts and calorie estimates and charts them in the companion app beside your heart-rate and sleep data, for general fitness awareness rather than clinical measurement.
O2Max is designed to work with iPhone and Android through its companion app and Bluetooth connection. Check current operating-system and app requirements because compatibility can vary by phone and app version.
There is no required monthly REXQU subscription for the advertised watch features. Companion-app availability and requirements can change, so check the current product information during setup.
The page lists a published 7–15 day range. Actual runtime depends on sensor use, display settings, background tracking, workouts and other features.
O2Max has an IP67 water-resistance rating for everyday exposure. The page does not position it as a swimming watch, so follow the current care instructions and avoid swimming unless product documentation specifically permits it.
REXQU offers a 30-day return window subject to the Returns & Refund Policy. Review the policy for eligibility and return instructions.
Choose O2Max for wrist SpO₂, on-demand ECG and daily wellness trends in a classic round design. Today: $169.97 with free shipping and a 30-day return window.
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