Lights show on BONDS by IQOS to alert you to an issue:
No lights: Turned off or battery depleted.
Yellow/orange light blinks 3 times: Battery is low.
Red blinking light: There’s either a device error, which a reset may fix, or the device is charging too slowly.
All lights blinking white 2 times: Device is outside of operating temperature range (0-40°C). Let it cool down or warm up.
Lights pulsing up and down: Device is in cool down mode (triggered after 3 consecutive sessions). Give it 4 minutes to cool.