FEATURES  Portable speaker system  Built-in microphone with call answering function  Built-in 300mAh rechargable lithium ion battery  Continuous music playback up to 4 hours at 50% volume  Continuous talk time up to 4 hours at 50% volume  Audio line-in jack  Bluetooth V2.1  SPECIFICATIONS  Total system power (RMS) SW  Frequency response: 20Hz-20KHz  Driver impedance: 4ohm  Driver size: 40mm