Product number: E58. 3.7V 3800mah Battery for ZLL SG901 MAX Drone Quadcopter. 3.7V 1800mah Battery for ZLL SG901 Pro Drone Quadcopter. Original 7.4V 2500mAh Battery for 4DRC F11 Drone Quadcopter. Original 3.7V 2000mah Battery for 4DRC F9 Drone Quadcopter.