Insert CR2032 battery (remove plastic cover from it) and put it back, the cadence sensor is very easy to assemble, it is very easy to fix with thick rubber bands in the kit. It's significantly cheaper than the alternatives offered by Wahoo, it connects very quickly and easily via Bluetooth to the Wahoo app on my phone (it's best to put the sensor on the pedal first and then pedal, for the sensor to start working, so the Wahoo app can quickly detect it). Overall I am very happy with it and can only recommend it.
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