... Charging Time: about 3 hours * FM Transmitter to all 2.5mm and 3.5mm digital player* Power Source ... Electric.* Recharge it under sunlight or with USB cable. * Compatible with: iPhone, iPod, all kinds of cellphone, PDA, Digital Camera, ... mobile phone, mp3 anytime anywhere. recharged by sunlight or electricity. Easy to take, use. 3:You ... , for it can transmit music of phones or mp3 and iPad to FM Radio