Compatibility and Two Years Warranty: Please check in for compatibility list(including but not limited). If you don't see your phone model, please contact us freely for compatibility guide advice. We promise 2-year warranty. In case there is any question or problem using the headset, please send us message. We will reply within 24hs ASAP. Great Durability: Light weight and tough design, stainless steel headband, superior quality speaker and microphone, reliable plastic parts. Reinforced cord built with Kevlar to withstand demanding environment and to protect against office chair wheels, sharp objects for daily use. Compete with Plantronic and Jabra expensive headset for all day long heavy use. Super Comfortable Headset: office headset with super soft protein leatherette ear cushion,user-friendly hygiene, adjustable headband to fit for different head sizes, ear cover rotatable,no pain no push to ears for all day long wearing. Microphone arm 330 degree rotable for wearing mic on either side, super call center headset for telemarketing and offices. High Quality Sound: Phone headset with noise cancelling microphone and HD audio sound ensure easy and clear communication for call centers, offices and home phones even in noisy environment. Wideband audio solution offers natural and clear hearing. Anti acoustic shock for hearing protection. Office headset with RJ9 jack for Avaya Nortel Aastra Allworx Alcatel Polycom 300 301 335 430 450 500 501 550 600 601 650 670 CX300 CX500 CX600 CX700 VVX300 VVX310 VVX400 VVX500 VVX600 VVX1500(included but not limited). Please see in the for more compatibility instruction.