GensAce 2 Pack of Ultra X (Tattu Plus) 6300 mAh 11.1V Lipo Battery Packs for Yuneec Q500, Q400 4K and Q500 G Quadcopter Drones Fits ALL Yuneec Q500 Models Self-balancing function Self-discharge function at 100%SOC Storage Over voltage and undervoltage alert function Cell abnormal alert function