DRONE RACER USB Twin Charger 0.2-1.0A Tweet Description Compatible Battery: Drone Racer 1 Cell Li-Po Battery (3.7V-1000mAh) Size: L82 x W70 x H29mm Other: Input power (USB): 5V 2A or above (recommended) charging voltage (Slot1): 4.20V, charging voltage (Slot2): 4.20V