Comdio 2.5mm Call Center Telephone Headset Headphone with Mic + Volume Mute Controls for Cisco Linksys SPA SPA921 SPA922 SPA941 SPA942 SPA962 303 501G 502G 504G 508G 509G 525G IP Phones (H203VP1) ONLY WORKS FOR SOME SPECIFIC PHONES. SEE COMPATIBLE PHONE LIST IN DESCRIPTION, BUY THE ITEM TODAY IF YOU HAVE ONE OF THE PHONE MODELS LISTED BELOW. Direct connect over the head headset headphone, No additional amplifiers or adapters required, Most easy setup headset solution. Superior quality sound with the flexible adjustable noise cancellation microphone. Super Lightweight, Super Durable Headset with Comfortable ear and mic cushions. In-line Mic Mute / Volume Control built in. For Mobile Phone with 3.5mm headset jack like iPhone Samsung LG HTC Blackberry Huawei ZTE...etc, please check our items: Comdio H103-35M1 or Comdio H103-35M2