AURA Strap 2 is powered by a replaceable round coin cell (type CR2025) for up to 6 months. To replace the battery you need:
1) Remove the backward cover with the included pick.
2) Remove the old battery and insert a new one with positive polarity upwards. Battery type is CR2025.
3) Place the cover and press until the "click" sound.
4) Your AURA Strap 2 ready to take a measurement!