4Call K500QJ25 2.5 Corded Headset with Noise Canceling Mic for Polycom Cisco Linksys SPA Grandstream Panasonic Gigaset & Zultys Office IP Telephone & Cordless Dect Phones with 2.5mm Headphone Jack WORKS ONLY FOR PHONES LISTED IN DESCRIPTION, BUY ONLY WHEN YOU HAVE ONE OF THE PHONES LISTED. CONTACT US FOR GUIDE IF YOU ARE NOT SURE ABOUT YOUR PHONE COMPATIBILITY BUY ONLY WHEN YOUR PHONE HAS 2.5MM STANDARD HEADSET JACK. CONTACT US FOR GUIDE IF YOU ARE NOT SURE ABOUT YOUR PHONE COMATIBILITY. SEE PART OF COMPATIBLE PHONES IN DESCRIPTION. 2.5mm Direct connect headset, no additional amplifiers or adapters required for office or DECT phones with standard 2.5mm headset jack. Adjustable fit headband and comfortable ear cushions enhance for wearing comfort, even for long periods. Single earpiece with noise canceling microphone for superior sound pick up even in noisy offices. The single earpiece means you can still confer with colleagues while you're wearing it. Flexible microphone boom, 270 degree rotatable, which adjusts to suit your preference, you can also choose to wear the microphone on either your right or left side. Quick disconnect feature enables you to disconnect quickly from the bottom half the cable, while still wearing the headset, With Mute / Volume Control built in.