With the Base battery charger, you can charge either 2 or 4 rechargeable AA or AAA batteries. The charger features 4 slots and an LED display that allows you to easily monitor the charging process. The automatic shut-off function prevents overcharging. When not in use, the battery charger can be easily stored due to its compact design. It fully charges AA and AAA batteries in 12 hours. This Energizer charger also comes with 2 rechargeable AA Energizer batteries and a USB charging cable.