POLY Savi W8220-M, MSFT. Product type: Headset, Wearing style: Head-band, Recommended usage: Office/Call center. Connectivity technology: Wireless. Ear coupling: Supraaural, Headphone frequency: 20 - 20000 Hz, Impedance: 32 ?. Microphone type: Boom, Microphone frequency: 100 - 6800 Hz, Microphone sensitivity: 112 dB. Battery technology: Lithium Polymer (LiPo), Battery capacity: 700 mAh, Talk time: 13 h