This is a universal USB charger for eGo batteries and it works really quickly. It works with many different types of batteries such as the Mini eGo battery. eGo K 13000mah, eGo-K 1100mah, eGo-K 900mah, eGo Q 900mah, eGo Q 650mah, eGo-K 650mah, Imist 1100mah, Imist 900mah, Imist 650mah, V.V. 900mah and V.V. 650 mah. It normally takes just 2 hours to charge a 650mah battery completely, which is significantly quickly than some other types of chargers. So that you know when it is fully charged there is a LED, which will turn from red to green when charging is complete. Make sure check the battery is compatibility before buying or using it. Stop charging the battery once it is fully charged. As a safety precaution, never overcharge batteries and disconnect them from the USB as soon as they are charged.