This fast Charger comes with 4 AA or AAA Batteries . Worldwide Use AC100-240V,50/60Hz varriable voltage allows automatic use in diferrent countries . The timer control shuts off after 8 hours to prevent overcharging. It has reverse polarity protection also to help prevent incorrect battery insertion. It features 0 voltage jump start.and Features like Trickle charge. i.e. the charger stores some charge so that even when the battery gets charged even when it has 0V. The charger has 4 LED indicators to indicate the charging status. The charger uses low charging current, hence your batteries will have a longer lifetime. Needs an input of 100-240 V.