Call Center Hands-Free Headset + Adjustable Volume + Mute Control with Comfort Fit Headband for NEC Aspire Nortel M2616 M3904 Plantronics A100 T10 T20 T100 S11 S12 Aastra Telecom Shoretel Avaya Telephone Direct connect over the head headset, no additional amplifiers or adapters required. Built-in adjustable volume and mute control. Shirt clip included. Soft leathered ear cushions for all day comfort. Superior quality sound with the flexible adjustable microphone. Comfortable lightweight design, shirt clips included.