... used as external audio to connect with your MP3, MP4, CD, DVD, Ipod, iphone, GPS, PSP, ... and noise ratio of power amplifier.≥80dbloud speaker:1.77inch(external diameter 45mm)magnetic resistant ... SD card player directly4. Support USB flash drive player directly5.out put: rms6w(3w+3w)THD=10% 6.Speaker ... Size: 16cm *5.4cm *5.4cm 7.Battary: lithium battery and rechargerable. 600mAH Mini SD/MMC ...