Sony DRBT101/BLK Over-the-Head Style Stereo Bluetooth Headset (Old Version) Built-in microphone for mobile phone use (hands-free) with clear voice technology for best human voice reception Built-in Lithium ion rechargeable battery offers convenient charging via standard USB ports (cable included) Compatible with Bluetooth Version 2.0; supports A2DP, AVRCP, HSP, and HFP profiles Echo canceling technology to further enhance phone conversation Remote Control functions (AVCRP) on headset using multifunction button