2 Batteries & 1 USB Charger for Wonder Drone: 2 Li-Polymer Batteries 3.7V 300mAh. Comes with 2 Li-polymer 3.7V 300mAh batteries and 1 USB charger. Double flight time with 2 fully charged batteries give you a total flight time of ~12 minutes. Batteries need to be charged before first use. Never charge batteries for more than 45 minutes.