Digital Mr Delta 510 Battery Cartboy Fits Upto 2 Gram Carts Digital display representing voltage & temperature. 510 Cartridge is not included in the box. Battery: 650mAh Charging Port: Type-C Various Voltage: 2.8V / 3.4V / 3.8V To Adjust Voltage: Rapidly press the button 3 times within 1.5 seconds to change voltage Green Light Indicates: 2.8V Blue Light Indicates: 3.4V Red Light Indicates: 3.8V Preheating: Rapidly press the button twice within 1.5 seconds to preheat.