... external LI battery,500mAh/DC 5v 1.5"speaker,3W*2 the functions and the advantages of ... ,you can put it in your bag conveniently.4,without the supply of other power,its Li ... product feature Part number:SG-339 mini portable multimedia speakerinterface:USB,SD card,3.5mm stereo jacksupport resource ... Output power: 5W(2.5w+2,5w)Loud speaker specification:1.5cm ,4ouhm,3wfrequency response:1000hz-20khzsound& ...