The Efest Lush Q4 Battery Charger is a quad slot charger which automatically charges at 2A with a single battery and a 1A with dual batteries. It has a no button design with an LED battery life indicator. It lets you know when your batteries are charging and fully charged. The slots are independently monitored to provide an accurate and efficient charge. It features reverse polarity, short circuit, overcharge protection along with other safety features. This charger can charge different types of 3.6V/3.7V lithium batteries commonly used for e-cigs.