iDance HIPSTER 706 Headband Headphones - Black & Red High definition built in microphone Standby time of up to 75 hours, Continuous usage time up to 8 hours Frequency response: 20HZ-20KHZ, 40 mm Neodymium Speaker driver and Impedance 32 ohms Rechargeable lithium ion battery 3.7V 300mA, Charging thru computer USB interface/output DC5V/500mA charge