Round single Cartridge battery A: Features: * Battery mah : 320 mah * Size: 27.5mm DiaX 110 mm (Height) * With LED display; * Adjustable voltage by bottom button; * Voltage: 2.4V/ 2.6V/2.8V/3.0V/3.2V/3.4V/3.6V/3.8V/4.0V/4.2V * Activation ?Puff activate or Button Start Press Button function: (on bottom): 2 clicks pre-heat (15 seconds at 1.8V) 3 clicks adjust voltage (from 2.4V – 4.2V) 5 clicks on/off * Charging port: Type-C B: Advantage: * Suitable for 510 cartridge