2-Year Warranty: We offer 45 days money back and 2 years worry-free guarantee. Please check in the for compatibility list (including but not limited). For other landline phones, please contact us for compatibility guide or advice. Clear Chat & Durable for Call Center Using: Noise cancelling microphone reduces background noise and wideband audio solution enables this phone headphone to deliver more richer and natural sound. High-end materials and durable structure ensure your frequent uses in busy environments. Comfortable for All-day Wearing: Over-the-head Binaural Wearing Style, Lightweight Plastics Design, Soft Leatherette Ear Cushions, 330°Rotatable Microphone and Adjustable Headband to fit any head size. Acoustic Shock Protection Circuit for hearing protection to make you a full working day without discomfort. RJ9 Headset Compatibility: Callez corded phone headset is compatible with Avaya 6402D 6408D+ 6416D+M 6424D+M 8403 8410D 8434DX 4406D+ 4412D+ 4424D+ 4424LD+ 1120 1140 1165 1210 1220 1230 1408 1416 2410 2420 4610 4610SW 4612 4620 4620SW 4621 4621SW 4622 4622SW 4625 4625W 4630 4630SW 5410 5420 5610 56205621 5625 9404 9406 9408 9504 9508 DT1 DT3 DT5 QE4610 landline phones. [Not for Avaya J139 J169 1608 1616 9608G 9611G 9620 9621G 9630 9640 9640G 9641G and 9650 IP Phones]. Headset for Multiple VoIP Phones: But Not For Cell Phones & Computers. This office telephone headset with RJ9 headset jack is only compatible with some specific Landline Deskphone Models in description like Avaya Polycom ShoreTel Nec Mitel Allworx Plantronics Toshiba Zultys InterTel Siemens Rolm Aastra Packet8,etc. For other phones and models, please check them in the for compatibility list below.