This RJ9 Office phone headset is a 4-Pin RJ9 Crystal Jack Headset, it is ONLY compatible for CISCO landline telephones, NOT for Smartphones and Computers. (2.5mm plug, 3.5mm plug or USB plug are NOT included) Please read the compatibility information carefully before purchasing. For other phones, please Consult us for Compatibility Guide or Advice. Compatible Landline Phone List: Cisco IP Phones: 7920, 7931G, 7940, 7940G, 7941, 7941G, 7942, 7942G, 7945, 7945G, 7960, 7960G, 7961, 7961G7962, 7962G, 7965, 7965G, 7970, 7970G, 7971, 7971G, 7975, 7975G, 7811 7821, 7841, 78616821,6841, 6851, 6861, 6871, 6921, 6941, 6945, 6961, 8811, 8841, 8845, 8851, 88618941, 8945, 8961, 9951, 9971, 12VIP, 30VIP, 8865, CTS 500 Plantronics Amplifier: M10, M12, M22 & MX10 Amplifiers NOTICE: NOT compatible with Cisco Spa phone series and Cisco 7902, 7905, 7905G, 7906, 7906G, 7910, 7910+SW, 7911, 7911G, 7912 IP Phones. Crystal Clear Calls High sound quality RJ9 office Telephone headset provides natural and truly clear conversations, Noise Cancelling Microphone eliminates most background noise making you sound crystal clear and Acoustic Shock Protection (ASP) protects your hearing. All-day Comfort Weighs only 84g/2.97oz. Lightweight design with soft leatherette ear cushion and adjustable headband enables the desk phone headset all-day wearing comfortable without pressure. It protects your ears from getting hurt and gives your all day comfort. Previous page Noise Cancelling Mic Advanced noise cancelling mic reduces noise caused by background and delivers clearer conversations. 330° Rotatable Microphone Flexible and 330° rotatable mic can be on left or right side and capture better voice positioning. Adjustable Headband Flexible headband can be adjusted or bent to fit all head sizes and brings no burden to your head. Convenient In-line Controls Built-in Volume Control and Mic Mute Button makes work efficient. Easy to connect, ideal for office. Simple to Use 1.Plug RJ9 Jack to “Headset Port” of phone 2.Press “Headset Button” to activate headset for calling Next page 1 Noise Cancelling Mic 2 330° Rotatable Microphone 3 Adjustable Headband 4 In-line Controls 5 Simple to Use How long is the cord? The cord is around 77inches(6.4feet), and there is an extension coiling cable, so you can extend the cord to be around 80inches(6.7feet). Does this headset work for smartphone or computer? No, this is a telephone headset with RJ9 jack, it only works for some specific telephone model listed in description, NOT for smartphone or computer. Does this headset work for any desk phones with an RJ9 headset jack? No, this phone headset only works for some Cisco IP Phone models 7940 7941 7942 7945 7960 7961 7962 7965 7821 and other 79xx 78xx 68xx 69xx 88xx 89xx 99xx series in the list. For other phone models, pls consult us for compatibility guide or advice. Hello, is this compatible with my Cisco spa525G? No, this phone headset isn’t compatible with Cisco SPA phone series and 7902, 7905, 7905G, 7906, 7906G, 7910, 7910+SW, 7911, 7911G, 7912 IP Phone. It only works for some specific Cisco phone models, please check the compatibility list in description. Does this headset have mute function? Yes, this corded phone headset has microphone mute button and in-line volume control, you can mute/unmute the microphone and adjust the headset volume up/down.