Call Center Headset Headphones Ear Phone + Adjustable Volume + Mute Control for Polycom SoundPoint IP Phone Series, Models 300 301 430 500 501 550 600 601 650 Ip Telephone Direct Connect Over The Head Headset, No Additional Applifiers / Adapters Required. Built-In volume adjustable and mute button control. Shirt clip included. Soft Leathered Ear Cushions For All Day Comfort. Superior Quality Sound with the Flexible Adjustable Microphone. Headband Style with Single Earpiece for Great Sound Quality in One Ear. NOT for Cisco brand telephone