If your Strap 2 blinks every 2 seconds red light when you're touching electrodes, it means low battery. If the battery is low, after the measurement, the app will also notify you about a low charge level.
AURA Strap 2 is powered by a replaceable round coin cell (type CR1632) 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. The battery type is CR1632.
3) Place the cover and press until the "click" sound.
4) Your AURA Strap 2 is ready to take a measurement!