Dual Headphone 2.5mm Headset + Noise Cancellation Microphone with Volume + Mute Control for Cisco SPA Series, Polymcom Soundpoint, Grandstream Dual Headphones With Noise Cancelling Microphone Built-In Adjustable Volume + Mute Control Soft Leathered Ear Cushion For All Day Comfort Superior Quality Sound with Flexible Adjustable Microphone