【NOT for Cell Phones and Computers】COMPATIBLE with Yealink All IP Phones Avaya 1608 1616 9608G 9611G 9630 J139 J169 J179 Snom 300 320 360 710 821 870 compatible with Panasonic KXT 2260 7220 7330 7420 7433 7665 7740 Zultys ZIP 33G 36G 37G 33i 35i AltiGen IP805 Aastra 6737i. SEE MORE COMPATIBLE PHONE LIST IN DESCRIPTION. | Yealink IP PHONES COMPATIBILITY: This RJ9 phone headset for Yealink office phones SIP-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. | SUPER COMFORTABLE: Super lightweight landline phone headset with adjustable headband to fit all head sizes, soft leatherette ear cushion enhances all-day wearing comfort. Easy to set up, direct connect the headset to your phone, no additional amplifiers or adapters required. | CRYSTAL CLEAR CHAT: Corded office telephone Headset with flexible adjustable Noise Cancelling Microphone to reduce background noise. Acoustic Shock Protection Circuit to protect your hearing. Less noise, Clearer voice. | 1 YEAR WARRANTY: 30 days money back & 12-month worry-free guarantee. Perfect for Call Center, Telephone Counseling Services, Insurance, Hospitals, Office and Home. ONLY COMPATIBLE WITH SOME SPECIFIC PHONE MODELS LISTED IN DESCRIPTION (include but not limited). For Other Models, pls contact us for Compatibility Guide or Advice.