The PARD double battery charger is designed to efficiently and quickly charge two PARD Li-Ion 3200mAh, 3.7V 18650 & 21700 batteries. The battery compartments are spring-loaded, so the batteries stay in place while charging. The integrated power indicator will signify when the batteries are fully charged. The PARD double battery charger also features a built-in charging protection feature that eliminates the risk of overcharging the Lithium Ion batteries. pard usa PARD 2 Slot Battery Charger Fast Charging Solution for 18650 and 21700 Batteries