Plantronics Savi W745-M Microsoft Lync Wireless Headset (w/Spare Battery) Unlimited talk time with hot swappable battery and charger (included in the W745-M) Optimized for Microsoft Lync 2010. supporting one-touch call control with Office Communicator. Multi-device support: PC, desktop phone and cell phone (Bluetooth) Easily switch between and mix audio across devices Allow 3 additional headsets in a conference call.