This RJ9 office phone headset work for Yealink T19P, T20P, T21P, T22P, T23P, T26P, T27P, T28P, T30P, T31P, T33P, T40P, T41P, T23G, T27G, T29G, T31G, T32G, T33G, T38G, T40G, T41G, T42G, T46G, T48G, T49G, T41S, T42S, T46S, T48S, T42U, T43U, T46U, T48U, T53W, T54W, T57W, T55A, T56A, T58A etc. NOT FOR CELL PHONES OR COMPUTERS(Please check Headset Compatibility List）. | 【Crystal Clear Chat】: Wideband Sound telephone headset enables natural listening experience, noise canceling microphone provides greater focus and concentration by blocking background noise, plus acoustic Shock Protection to protect your hearing. Less noise, Clearer voice. | 【Lightweight and Comfortable】: A600Y yealink headset Rigorously tested ergonomic design provides all-day comfort. Ultra-soft, large protein ear cushions and an adjustable headband distribute weight evenly, so your last call of the day feels as comfortable as your first. | 【Convenient In-line Controls】: Arama wired phone headsets for office phones with Convenient inline volume and mute controls extension cord allows a more flexible listening experience. 5.4ft long cord offers flexibility to move around,designed to keep pace with the demands of work and life. | 【Built to last】: Arama phone headsets for office phones with precision design, quality plastics, durable and advanced.