Polycom IP Phones Compatibility: This RJ9 office phone headset works for Polycom VVX411 VVX311 VVX410 VVX500 VVX400 VVX300 VVX301 VVX310 VVX501 VVX401 VVX201 VVX601 VVX250 VVX350 VVX450 VVX101 VVX150 VVX330 VVX600 CX300 CX500 CX600 CX700 SoundPoint 300 301 335 430 450 500 (rev. E or later) 501 550 560 600 601 650 670. NOT for Polycom SoundPoint IP320, 321, 330, 331, Pro SE-220, SE-225. | RJ9 Jack Headset Compatibility: Callez telephone headset is ONLY Compatible with Some Specific Landline Phone Models from Polycom Avaya Plantronics Mitel NEC Shoretel Aastra Allworx Zultys Nortel InterTel AltiGen and etc. Please check Compatible Phone List in description before purchasing. NOT FOR CELL PHONES OR COMPUTERS. | Crystal Clear Chat: RJ9 phone headset features a noise-canceling microphone to reduce background noise and provide excellent sound quality. Flexible microphone boom captures sound well, plus acoustic shock protection circuit protects your hearing. | Super Comfortable: Designed with soft leatherette ear cushions, callez phone headsets for office phones fit nicely on the ear. The comfortable over-the-head design and adjustable headband enable this landline phone headset comfortable to wear for extended periods of time. | Warranty Guarantee: Callez phone headsets are backed by a 45-day money back and 24-month worry-free guarantee. Please review the Compatibility List prior to purchase. For other phones not listed, please contact us for Compatibility Guide or Advice.