Features: Suitable for multi-drones: Syma X5 series GoolRC T6 T33 T37 JJR/C H43WH H31 H37 RC quadcopter and so on. Fast charging: 4 in 1 battery charger, can charge 4pcs 3.7V batteries at the same time, saves a lot of charging time. Indicator LED available: LED light up indicates charging process, led light off indicates charging complete. Easy to use: plug the your batteries to the charger and then plug the USB charger to the PC. Safe: high-power and high-performance circuit.