Sky Viper Drone Rechargeable LiPo Extra Battery - 3.7V 650mAh Double your flight time means double your fun! Double flight time with a second battery Works with Sky Viper Hover Racer, v2400 HD Streaming Video Drones, and s1700 Stunt Drones 650mAh 3.7V lithium polymer (LiPo) battery Charge time is about 30 mins Rechargeable battery pack