Polar presents an update on the flagship M400 running shop-- the M430, a wearable featuring wrist-based heart rate sensors within a slightly thinner and lighter design.
The M400 is very similar to its predecessor, consisting of a rounded-square module with 5 physical buttons and a soft-touch perforated silicone strap reminiscent of that included with the Nike Apple Watch Series 2. The module weighs 51g and carries 6 LED lights for optical heart rate sensing, built-in GPS, 240mAh battery and a monochrome display.
Users can pair the M400 with a chest strap (such as the Polar H10) for more accurate heart rate data, although the company says it has improved the biometric algorithms inside the watch. The accelerometer adds distance pace and distance metrics for indoor running on treadmills, while pairing with the Polar Flow companion app adds "Smart Coach" features with details on runs, aerobic and anaerobic activities, immediate and residual training load, and free guidance based on gender, weight, age, experience and running time.
In addition the watch shows smartphone notifications, although interactions with such notifications are fairly limited. It shops from May 2017.