Features: Super flying combo: includes 4pcs GoolRC 400mAh 3.7V 25C LiPo batteries and 4-in-1 fast smart charger. Suitable for multi-drones: Holy Stone HS170 Hubsan H107C H107D Syma X11 X11C and so on. Fast charging: charge 4pcs battery at one time, about 1 hours for fully charge. Rechargeable: durable and can be charged multiple time. Indicator led available: led light up indicates charging process, led light off indicates charging complete. Easy to use: plug the batteries to the charger and then plug the USB charger to the PC.