Doteco DC650 Dual Cartridge 510 Battery Features *510 Cartridge is not included in the box* Battery Capacity: 650mAh Display- Digital Screen Working Voltage: 1.8V/2.4V/3.0V/3.6V/4.2V Two 510 Thread Connectors for Long/Short 510 Cartridges 10-second 1.8V Preheating Function Magnetic Connection Compatible with Most 510 Thread Cartridges Charging Port: Type-C