Crystal Clear Chat Wideband Sound telephone headset enables natural listening experience, features Noise Cancelling Microphone to reduce background noise. Every word comes through crystal clear for you and the other parties. Convenient In-line Controls Professional Volume Control and Mute Switch built in. Easily adjust the headset volume up/down, mute/unmute the microphone. Easy to use, just plug the headset into the RJ jack on your phone and you’re ready to talk. Wide Compatibility Office phone headsets rj9 Jack work for Plantronics Amplifier Cisco IP Phones for use with most corded and cordless phones possessing a standard rj9 jac Noise Canceling Microphone Features Noise Canceling Microphone to reduce background noise, make your calls clearer. Comfortable Ear Cushion Super soft high quality leatherette ear cushion and Rotatable Earpiece enhance all-day wearing comfort. Soft T-Pad Precision construction allows you to wear the headphones securely and comfortably all day long. Friendly Notes: This headset only works for Cisco landline phones with RJ9 Jack, NOT for Smartphones and computers. (2.5mm plug, 3.5mm plug or USB plug are NOT included in the package). Do not buy the item if you can’t find your phone model in lists, pls consult us for compatibility advice. Compatible Phone List (Include but not limited): Plantronics: M10, M12, M22 & MX10 AmplifiersCisco IP Phones: 7931G, 7940, 7940G, 7941, 7941G, 7942, 7942G, 7945, 7945G, 7960, 7960G, 7961, 7961G, 7962, 7962G, 7965, 7965G, 7970, 7970G, 7971, 7971G, 7975, 7975G, 6821, 6841, 6851, 6921, 6941, 6945, 6961, 7811 7821, 7841, 7861, 8811, 8841, 8845, 8851, 8861, 8941, 8945, 8961, 9951, 9971 NOTE : Not compatible with Cisco Spa phone series. If necessary, please purchase Wantek 2.5mm headset, ASIN: B06XS87YBG Not compatible with some Specific Cisco Phone Models such as: 7902, 7905, 7905G, 7906G, 7910, 7910+SW 7911, 7912 IP Phones