Bluetooth version : V4.1 â?¢ Frequency response : 20Hz-20KHz â?¢ Impedance : 4 ohms â?¢ Working voltage : 3.7V â?¢ Charging voltage : USB 5V 500mA â?¢ Play time : 4-8 Hours â?¢ Charging time : 2-3 hours â?¢ Bluetooth transmission : 32ft â?¢ AUX Audio : 3.5mm standard audio line â?¢ TF Card : Support up to 32GB â?¢ 3 Months Warranty