ONLY WORKS with Plantronics M10, M12, M22 & MX10 Amplifiers and CISCO IP phone models : Cisco IP 6921, 6941, 6945, 6961, 7821, 7841, 7861 Cisco IP 7931G, 7940, 7940G, 7941, 7941G, 7942, 7942G, 7945, 7945G Cisco IP 7960, 7960G, 7961, 7961G, 7962, 7962G, 7965, 7965G Cisco IP 7970, 7970G, 7971, 7971G, 7975, 7975G Cisco IP 8811, 8841, 8851, 8861, 8941, 8945, 8961, 9951, 9971 or AVAYA CALLMASTER V VI ONLY COMPATIBLE FOR SOME SPECIFIC PHONE MODELS LISTED ABOVE. Not compatible with Cisco Spa phone series. FOR OTHER PHONE MODELS, PLS CONTACT US FOR COMPATIBILITY GUIDE OR ADVICE.

Comfortable wear, compact appearance, human engineering design, Can be uninterruptible using.The headset clip can be stretched freely and comfortable wear. Superior Quality Sound with the Flexible Adjustable Microphone. Direct Connect Over The Head Headset, No Additional Applifiers / Adapters Required. ONLY COMPATIBLE with Cisco Unified IP Phones:7940 7940G 7941 7941G 7942 7942G 7945 7945G 7960 7960G 7961 7961G 7962 7962G 7965 7965G 7970 7970G 7971 7971G 7975 7975G 6921 6941 6945 6961 7821 7841 7861 8811 8841 8851 8861 8941 8945 8961 9951 9971 and Amplifier: M10 M12 M22 & MX10 Vista Modular Adapters.