This Corded monaural telephone headset for Cisco phone delivers crystal-clear voice quality and can be comfortably worn over long periods of time, ideal choice for busy offices, telemaketing centers, call centers etc. Its built-in enhanced noise-cancelling microphone effectively reduce up to 85% background noise and let your caller hear your every word clearly, and the excellent sound quality gives them the feeling they’re having a “face to face” conversation. ✔ Loud and clear sound ✔ Noise cancelling microphone for clearer voice transmission ✔ Built-in acoustic shock protection to protect hearing ✔ Durable construction to withstand the most demanding environments ✔ Soft leatherette ear cushions for all day comfort ✔ Fully Adjustable ‘Surefit’ Headband fits small or large head ✔ Quick disconnect allow users to leave desk quickly without taking headset off Headset Compatibility (Included but not limited) This corded phone headset with RJ9 jack work with most Cisco phone with RJ9 headset port. Cisco 12 VIP, Cisco 30 VIP, Cisco 6841, 6851, 6921, 6921, 6945, 6961, 7821, 7841, 7861, Cisco 7931G, 7940, 7940G, 7941, 7941G, 7942G, 7945, 7945G, 7960, 7960G, 7961, 7961G, 7962G, 7965G, 7970, 7970G, 7971, 7971G, 7975, 7975G, 8811, 8841, 8845, 8851, 8861, 8865, 8941, 8945, 8945G, 8961, 9951, 9971, CTS500 Note: Please do not buy this headset for Cisco SPA Series phones!!!