Slim style variable voltage battery with 510/usb charger.. Perfect for all of your pre-filled cartridges with 510 compatibility. Choose your desired voltage to vape your concentrate at to get the best flavor possible. 350 mah, 3 voltage settings. Green 3.4V,. Blue 3.7V. Red 4.0V. 5 clicks on/off, 3 clicks to change the voltage, 2 clicks to preheat. Use with CE3/O-Pen atomizers.