Check the listing for details. Plantronics Blackwire C520-M Stereo Computer Headset USB Connection Black TESTED. Color: Black, Condition: Used. Listed at 11.39 USD. Enjoy crystal-clear audio quality during your computer sessions with this Plantronics Blackwire C520-M Stereo Computer Headset. The headset comes in sleek black color and has an adjustable headband that ensures a comfortable fit for long hours of use. It has a USB connection that enables easy plug-and-play, making it ideal for busy computer users. This headset features a double earpiece design, with one for each ear, and a microphone mute button that allows you to easily switch between listening and talking modes. The noise cancellation feature eliminates distractions and ensures that you can focus on your work or calls. Additionally, the headset has an ear-cup design that provides excellent noise reduction, ensuring that you can hear clearly even in noisy environments.