RJ9 HEADSET COMPATIBILITY: NOT for Cell Phones and Computers. ONLY COMPATIBLE with Plantronics M10, M12, M22 & MX10 Amplifiers or Some Specific CISCO IP phone models: 6821, 6841, 6851, 6921, 6941, 6945, 6961, 7811, 7821, 7841, 7861, 7912, 7920, 7931G, 7940, 7940G, 7941, 7941G, 7942, 7942G, 7945, 7945G, 7960, 7960G, 7961, 7961G, 7962, 7962G, 7965, 7965G, 7970, 7970G, 7971, 7971G, 7975, 7975G, 8811, 8841, 8845, 8851, 8861, 8865, 8941, 8945, 8961, 9951, 9971. | ALL DAY COMFORT & QUICK DISCONNECT CORD: Super lightweight wired Hands-free RJ9 Telephone Headset Compatible with Cisco IP Phones with adjustable headband to fit all head sizes, high quality and soft leatherette ear cushion enhance all-day wearing comfort. Professional Mic Mute / Volume Control built in. Quick Disconnect(QD) feature enables you to walk away from the desk without taking headset off. | ULTRA DURABLE: Precision design, quality plastics, unibody headband construction, superior quality microphone makes this office phone headset with RJ9 jack sturdier and more durable. for Call Center, Office, Home, Telemarketing, Business, Phone sales, Insurance, School, Hospitals, Banks, IT Department, Customer Services, Consulting, Conference Calls. | CRYSTAL CLEAR CHAT: Wideband Sound RJ9 Call Center Phone Headset with microphone Compatible with Cisco landline phones enables excellent sound quality for natural listening experience, features Noise Canceling Microphone to reduce background noise, Acoustic Shock Protection Circuit to protect your hearing. | ALL DAY COMFORT & QUICK DISCONNECT CORD: Super lightweight wired Hands-free RJ9 Telephone Headset Compatible with Cisco IP Phones with adjustable headband to fit all head sizes, high quality and soft leatherette ear cushion enhance all-day wearing comfort. Professional Mic Mute / Volume Control built in. Quick Disconnect(QD) feature enables you to walk away from the desk without taking headset off.