1,rechargable mini digital speaker 2,Support USB/SD card 3,Built-in rechargeable lithium battery 4,Plug ... 2,Built-in rechargeable lithium battery 3,Support SD card/USB Flash Driver 4,Output:3W*2 5,Speaker size:40mm ... to noise ratio > 70db 8,Power:USB DC5V 9,Impedance:4 OHMColorBlack,blue,red,green USB SD card speaker for promotion gifts