The ScanWatch 2 is equipped with a battery that according to Withings can go up to 30 days before needing to recharge. However, as you understand battery life is highly affected by use, and in our usage, which included monitor all day and night and during sleep hours, we managed to get around 18 days with a single charge and had around 15% of juice left. In our opinion, this is a great score and probably with less monitoring, usage could get to 20-25 days. The ScanWatch 2 will recharge to 80% in about 1 hour and to 100% in about 2 hours from zero.

The device doesn't emit serious radioactive waves and according to Withings, the maximum power of ScanWatch is 0.6mW and therefore does not exceed the applicable RF exposure limits of 2000mW. Manufacturers whose products emit very little (less than 20mW) are exempt from the display and calculation rules, which is why the SAR is not displayed on Withings specs.

The Bluetooth connection is not necessary at all times for the watch to work. You ScanWatch can keep data in memory if you would rather like to sync it manually. To do so, open the Withings App and turn the Bluetooth of your mobile device on. When you do so, your ScanWatch automatically syncs your data with the app. The product can store up to 7 days of data.

ScanWatch 2's menu can be displayed in English, French, German, Spanish, and Italian. However, ScanWatch 2 can display notifications in all languages. ScanWatch 2 doesn't include a built-in GPS, so it needs to be connected via Bluetooth to activate the connected GPS for all distance-based outdoor activities. You will need to enable the location settings on your phone for this feature to work. 

You should not use ScanWatch 2 if you wear a pacemaker or other internal medical device. A pacemaker circulates electrical signals in your body, which may induce wrong ECG measurements from the watch. Withings devices are connected via Bluetooth and/or WiFi. This means that they radiate electromagnetic fields that may interfere with other medical devices. If you have a pacemaker or another implantable active medical device, use precautions with connected objects. Please check with your doctor for detailed information before using these items.

The stock elastic band, while seems very sold, was for our wrist rather annoying and we liked the extra (+45 Euro) full leather Withings band. Of course, you can use any band with a 20mm width from other manufacturers. The Scan Watch 2 looks very classy and the build quality is very high. The simple design helps you with a corresponding wristband to use either for everyday use or for sports action as well. For the bottom walk goal indicator, we didn't find much use. The OLED screen is clear to see and bright enough for day use and you can set the wrist twist to get it light up when you need it. The center / main working button can be pressed one to light up or shut down the OLED screen. By rotating you can cycle between BPM, temperature, steps, walking distance, Floor, workout, ECG measurement, SPO2, breath, Clock alarm, Settings, Calories, and of course date/time. The center button rotation is smooth, even though sometimes it needs some extra effort to cycle between modes. The Scan Watch during our testing did recognize walking sessions, even sometimes mislabeled them as Cycling, which can be later edited at the Withings App.

The Withings App is nicely designed and will hold all the needed information about yourself if you are using Withings products (like watches, scale, etc..). The graphs are nice and you can get statistics from all measurements. The ECG function is nice to have medically graded and doesn't require any extra calibration from other sources. The steel of the case is hard, and even accidentally bumping into a car bumper, did leave a small mark. After using 25 days the watch we noticed some very thick lines on the watch case, even if that is expected. The watch crystal is made out of sapphire and it's hard enough to survive everyday use. The Scan Watch 2 is rated at 5ATM, which has to do with water resistance, and means that the watch is water resistant up to 50 meters in depth for 10 minutes. The ATM or “atmosphere” is the amount of pressure a watch can withstand. The Scan Watch 2 can be used for shallow-water activities like swimming in a pool or ocean, with the included elastic band. After all, Withings does offer swimming activities for measurement.

The Withings HealthSense operating system seems fast at the watch and didn't show any weird issues during our testing. We like the fact that Withings will continue to evolve and improve the Scan Watch 2 features/performance.

Apart from the good stuff, we left with a desire for a bigger watch, like 46mm diameter, which may have a higher OLED display and bigger battery as well. Don't get me wrong, 42mm is enough for many people, however, it's a matter of personal taste as well. The Scan Watch 2 also doesn't have GPS included, the E-sim function, which means you have to carry around your connected phone for tracking activities. Also, the sleep tracking feature wasn't 100% correct, since sometimes staying still in bed, is measured as a sleep session, when in reality we were just looking at our smartphone.

Overall the Withings Scan Watch 2, is the perfect solution for people who like classically designed watches with dials and at the same time want everyday health measurements that are medically graded. The addition of human monitor temperature is very useful to check out easily if your skin temperature has increased or decreased. For the retail price of 350 Euro, we find the Scan Watch 2 to be much more useful compared with other "smartwatches", which may have OLED screens as well, however, they sport much lower battery life, which is a big deal for our daily use...After all who wants to charge their watch day by day?