Compatible with following Polycom phone models: VVX201, VVX300/310/311, VVX400/410/411, VVX500, VVX 600/601, SoundPoint 300 301 335 430 450 500 (rev. E or later) 501 550 600 601 650 670 And other Telephone Models: AVAYA 1408 1416 5410 ShoreTel 230 420 480 Aastra Allworx Adtran Alcatel Lucent AltiGen Comdial Digium Plantronics MiVoice. For other phones, pls contact us for Compatibility Guide or Advice. | Ultra durable headset with reliable structure, build for last. Six levels of adjustability and a lightweight design ensure all day comfortable wearing. You can even pull or bend the headband for personal optimal fit. | HD Voice for Clear Communication: 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. | Monaural headset for those who prefer to leave one ear open, professional Volume Control and Mute button built-in.ideal for Call Center Service, Telephone Counseling Services, Insurance, Hospitals, Banks ect. | Super lightweight office phone headset with adjustable headband to fit all head sizes, high quality and soft ear cushion enhance your wearing comfort while long time conversation. Compete with Plantronics or Jabra heavy duty Headsets. We offer 45 days money-back guarantee and 24 months warranty.