Crystal Clear Chat: Specially designed RJ9 phone headset work for Cisco phones providing high-definition and crystal-clear communication, and noise cancelling microphone blocks out unwanted background noise and pick up loud and clear sound which makes you feel that you are having a face to face conversation. What's more, single earpiece headset can be worn on either side and you can still communicate with your colleague while wearing it | Productivity and Extended Comfort: Call center telephone headset with microphone allows you to work efficiently and comfortably. You can concentrate on the conversation while working on the computer during conference calls. With MKJ phone headset for Cisco phone, you don't need to cradle the phone handset between the head and shoulder which caused pain in the neck. Adjustable headband will fit all sizes head and the soft ear cushion ensures added comfort even for long-time wearing | Great Durability: High-end materials and durable design ensure the wired headphones with microphone withstand the constant demands of all-day use in busy environments. The built-in reinforced cord will protect the headset against office chair wheels, and sharp objects on daily use. Stainless steel headband, superior quality speaker and noise cancelling microphone, and reliable plastic parts make this headset durable enough even for busy environment | Hearing Protection: MKJ telephone headset for Cisco phones corded RJ9 with built-in hearing protection circuit will provide users with safe and comfortable audio experience. It protects you from long term daily sudden sound burst, any sound above 118db is filtered out. It is suitable for those who takes a large volume of call every day, including call center agent, customer service, telemarketing workers etc | RJ9 Headset Compatibility: This noise-canceling Cisco headphones for work allow you to deal with other tasks during calls, and it works with most Cisco phones with RJ9 headset port, such as 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 | Telephone Headset with RJ9 Jack: This wired headphone with mic only compatible with Cisco phone with RJ9 headset port, please do not use it on Cisco SPA seires phone or computers