Plantronics C725 USB Computer/PC Headset – Introduction, Features and Benefits. Plantronics C725 USB Computer/PC Headset: The new Plantronics Blackwire C725 USB Headset is a dual-ear headset that has a microphone. One great thing about the C725 is how easy this headset is to put on, configure, and adjust. The speakers rotate out, so they can be easily adjusted for each person. The headset has extremely soft … Continued