The steps for checking battery level on your IQOS ORIGINALS device are easy to follow. They just differ slightly for each device:
For IQOS ORIGINALS DUO, press and release the Pocket Charger Button. This turns on the status light button for 3 seconds. If 4 LEDs illuminate this indicates your device is more than 75% charged while 1 LED illuminated means your need to charge your device.