Polar was once the market and quality leader in heart rate watches. Obviously still rests you look at Polar on this ancient glory. Professionally, I've been using for many years RF knife, of Polar I have separated myself for quality reasons a few years ago. In addition, the question dealing with the Polars personal data of users has already been frequently discussed here. Well I hoped with the M400 on improvement, unfortunately, I was disappointed. You can about the size of the clock and the length of the bracelet still be divided, but a Heart Rate NOT the heart rate is indicating pointless! The sensor is allegedly linked with the clock, but unfortunately the clock shows rarely the heart rate. Some times it worked, but usually not. Mind you, other devices (mobile phones, ergometer, etc.) recognize the sensor and display the RF, not the clock. The manual does not help, the service has not yet responded to my emails. Therefore, the clock goes back and I'll stay with Garmin.
