The charger is available in a set with four eneloop AA batteries, which are already pre-charged during the production process and ready to use right out of the box. Eneloop rechargeable batteries combine the best features of rechargeable batteries and conventional batteries. Possibility to charge 4 AA / AAA batteries; can be used anywhere in the world (100-240 V); compatible batteries: AA x 1, 2, 3, 4 / AAA x 1, 2, 3, 4 cells; charging time: AA: about 7 h [2,000 mAh]; AAA: approximately 6 hours [800 mAh].