It monitors health indicators: it counts your heart rate, steps, activity, and measures your sleep and recovery after exercise. But its main feature is that there is no subscription fee for the app. A Whoop subscription in the US costs between $240 and $360 per year. The Polar Loop costs $200 once, and replacement straps cost another $30 each. But there are no subscription fees (at least for now), and the Polar app is free.

The company claims that Polar Loop works for up to eight days without recharging and can store four weeks of data without connecting to a smartphone