Telephone Headset for Cisco Phone: MKJ telephone headset with RJ9 Jack works on most Cisco phones (CISCO SPA is not inclueded), such as Cisco CP-7821, 7841, 7861, 7931G, 7940, 7941G, 7942G, 7945G, 7960, 7961, 7962G, 7965G, 7975G 8811, 8841, 8845, 8851, 8861, 8865 and 8900, 8941, 8945, 8961, 9951, 9971 etc. | Crystal Clear Sound: MKJ Cisco phone headset delivers crystal clear sound during conference calls. The superior noise cancelling microphone blocks out unwanted background noise and pick up loud and clear voice, this landline headset for Cisco phones is ideal for noisy call centers as it alows you to concentrate fully on the call, also the binaural type headset keeps the noisy distractions from your attention. | Ultra Durability: Sturdy yet comfortable wired headphone for call center withstands the most demanding environments. MKJ telephone headsets are durable for heavy calls in busy offices, the reinforced is built to withstand the demanding environment and is protected against office chair wheels, sharp objects on daily use, lightweight and stainless steel headband provides high strength to withstand the lasting use. | All-day Comfortable Wearing: MKJ office phone headset comes with lightweight and ergonomic design to ensure comfortable wearing even for long phone conference calls. The lightweight materials, soft ear cushion, adjustable headband and and flexible microphone boom provides users with comfortable wearing experience, and will not cause pain or fatigue for long wearing. | Hearing Protection: MKJ RJ9 Cisco headset features acoustic shock circuit to against acoustic injury and sudden sound burst above 118db. Professional ergonomic headset is specially important for people who are on the phone all day long, such as call center agent, home phone job, telemarketing insurance, etc. | Not for Computers: This is a RJ9 phone headset for Cisco phone, it does not work on computers pc or laptop.