‎Polyester

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Elastic
HOOK AND LOOP CLOSURE – NO MORE loose ends – this pair comes with easy to use adjustable hook and loop closure

WORKS WITH EVERYTHING: Polar HRM works with many sports and smart watches (Polar, Garmin, Apple, Suunto, etc.), Polar Beat, fitness apps such as Strava and Nike, and ALL HRM compatible Cardio Equipment
SUPREME ACCURACY: Widely recognized for its top precision by many sources, Polar H10 is the most accurate heart rate sensor in Polar’s history. Polar H10 provides top quality heart rate measurement and it’s the choice of many pro athletes.
CONNECTIVITY: Bluetooth, ANT+ and 5 kHz provide an excellent variety of connection options (e.g. with Peloton). You can use Bluetooth and ANT+ connections simultaneously as well as two Bluetooth connections simultaneously.