Comdio CH401VA3 Wired Call Center Phone Headset + Volume Mute Control for Aastra, Allworx, Altigen, Avaya, Nortel Meridian, Plantronics T20, Talkswitch ESI Doro Hybrex Cable & Wireless Telephones Direct connect over the head headset headphone, No additional amplifiers or adapters required. Superior quality sound with the flexible adjustable noise cancellation microphone. Most easy setup headset solution, Comfortable ear and mic cushions, Super Lightweight, Super Durable Shirt clip included, Mic Mute / Volume Control built in. SEE COMPATIBLE PHONE LIST IN DESCRIPTION, BUY THE ITEM TODAY IF YOU HAVE ONE OF THE PHONE MODELS LISTED BELOW.