Wantek Corded Mono RJ9 Office Phone Headset Works for Cisco Phones Need to talk online long hours everyday? Such as Call Center Service, Conference Calls, Telemarketing, Banks, Office, Business... or other similar situations? Try the most affordable Wantek 4-Pin RJ9 Telephone Headsets, you will win Crystal Clear Call, hearing protection and All Day Wearing Comfort! This headset ONLY comes with RJ9 jack for some Cisco Phones, NOT come with 2.5mm jack, 3.5mm jack or USB jack. (DO NOT BUY IT FOR CELL PHONES OR COMPUTERS). Compatible Landline Phone List : Cisco IP Phones: 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 8941, 8945, 8961, 8865, 8941, 8945, 8961, 9951, 9971 Modle: KX-UTG200B, KX-UTG300B Modle: M10, M12, M22 & MX10 Amplifiers NOTICE: Not compatible with Cisco Spa phone series. Not compatible with Cisco 7902, 7905, 7905G, 7906, 7906G, 7910, 7910+SW, 7911, 7911G, 7912 IP Phones. If necessary, please purchase another compatible headset, ASIN: B093PTJK3K (Search the ASIN # on Amazon will get you to the product page) Friendly Notes: This headset ONLY works for some Cisco landline phones with 4-Pin RJ9 Jack, NOT for Smartphones and computers. If necessary, please purchase Wantek 2.5mm headsets, 3.5mm headsets or USB headsets