Blackwire 300 series p/n: 85619-02c320 (bulk product) (stereo). Enter uc with the best-featured headset you never thought your budget could afford. Blackwire 300 series usb headsets are a simple-to-use, comfortable, and durable choice for conference calls, web-based training, and pc multimedia applications. Inline controls make it simple to answer and end pc calls and control volume and mute. The lightweight metal headband provides durability while delivering a comfortable and secure fit, while the unique dynamic eq feature optimizes sound quality and adjusts settings on the fly, creating outstanding sound for voice, music, and multimedia.