The Nitecore Q4 in is compatible with almost all types of rechargeable batteries. The charger utilizes four bays to independently charge different batteries simultaneously. Features Capable of charging 4 Li-ion batteries simultaneously Monitors and charges each of the 4 slots independently Features two charging modes (constant current and constant voltage) Automatically detects power level of batteries and selects the appropriate voltage and charging mode Automatically stops upon charging completion Overcharging protection Reverse polarity prevention and short circuit prevention Designed for optimal heat dissipation Made from durable PC material