ScanWatch 2

Withings ScanWatch 2 is a watch from 2023, sitting in the premium band at an indicative $369.

It reads 19 of the 33 signals this comparison tracks. Full coverage of sleep and activity. Nothing at all from body composition. Rarer readings it does take: sleep apnea screening, AFib detection, ECG recording and sleep efficiency.

By sensor class: 1 at clinical grade, 7 at high accuracy and 4 at consumer grade. That grade is my classification of the hardware, not a lab test. Those readings come from an optical heart rate sensor, ECG electrodes, an optical blood oxygen sensor, a skin temperature sensor, a GPS receiver and an accelerometer. It records an ECG and screens for atrial fibrillation. Those are screening features, not a diagnosis. Blood oxygen is measured through the night, not continuously through the day.

Its 30 days per charge are the 5th longest of the 74 devices of its kind here that publish a figure. It has a PMOLED screen. No GPS of its own, it borrows the phone's. Rated 5ATM, fine for swimming. It weighs 34.6 g. Case size 38 / 42mm. No subscription is required.

Hybrid watch; medical ECG/AFib, on-demand SpO2, 24/7 TempTech skin-temp, VO2max, connected GPS, floors.