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