HEADSET RJ9 Jack: MKJ Corded RJ9 telephone headset for Cisco phones only works on Cisco 6921, 6941, 6945, 6961, 7821, 7841, 7861, 7931G, 7940, 7940G, 7941, 7941G, 7942G, 7945, 7945G, 7960, 7960G, 7961, 7961G, 7962G, 7965G, 7970, 7970G, 7971G, 7975G, 7985G, 8811, 8841, 8845, 8851, 8861, 8865 and 8900, 8941, 8945, 8961, 9951, 9971 (included but not limited). DO NOT BUY THIS HEADSET for CISCO SPA SERIES PHONE. | SUPERB SOUND QUALITY: Wired headset for Cisco desk phone is a great option for those who want exceptional sound and style. MKJ telephone headset for Cisco phones ensure high-definition sound crystal-clear conversations. The superior noise cancelling microphone filters out sharp breathing sounds and popping noises often heard during the call. This corded Cisco phone headset picks up your voice loud and clear, your caller will hear every word clearly. | HIGH DURABILITY: Made of high quality PU materials and plastic parts, also exquisite workmanship, Cisco phone headset corded RJ9 withstands the constant demands of all-day use in busy environments. And the reinforced cord is built to protect Cisco headphones against office chair wheels and sharp objects on daily use. MKJ phone headset for Cisco 8841 can fully adapt to 7x24 hours for high frequency. | ALL DAY COMFORT: The ergonomic lightweight design assure that Cisco headset with microphone can be all-day comfortable even for 8 hours wearing. This over-the-head Cisco CP-7841 headset has a slim, stylish, lightweight deisgn and comes with soft ear cushions for added comfort. Adjustable headband and microphone boom arm let you find the perfect fit. With Cisco 8851 headset, you can deal with multiple computer tasks during the phone call. | Designed for Call Centers and Offices: MKJ telephone headset with microphone works on Cisco phone allowing users to do multitasks. With crystal-clear sound, and all-day wearing comfort, call center staff can deal with large volumes of calls easily.