You can keep an eye on the battery life, when it's at 100%-60%, the display shows green. And when you're down to 20% or less, it switches to red. More about the VooPoo Argus E40 PodsThe VooPoo Argus E40 Pods made for the VooPoo Argus E40 Kit, boast a 2ml tank capacity for longer vaping sessions with fewer refills.