... USB Port 3. 4 Voltage adjustable 4. CE, FCC and Rohs EGO VV passthrough ego usb battery variable voltage EGO VV passthrough variable voltage for electronic cigarette, power ... pressing button will change the voltage, fast and simple;3. compatible with all Ego/510 threads (plus for difference ... Smaild, smart design, and longworking time, support various voltage.Any question pls fell free to ask me, I ...