2-YEAR WARRANTY: 45 days money back & 24-month worry-free guarantee for all telephone headsets. Ideal for Counselling Service, Business, Hospital, Call Center and more. Buy the item ONLY if you have one of phone models in list. For other phones, pls contact us for Compatibility Guide or Advice. ULTRA DURABLE: Precision design, high-quality plastics, uni-body headband construction, flexible metal mic boom make this RJ9 phone headset for office phones more durable and sturdier. SUPER COMFORTABLE: The light office phone headset with adjustable headband fits all head sizes, a flexible boom mic picks up your voice clearly, and soft leatherette ear cushions enhance all-day wearing comfort. Feel no burden during long-time work. CLEAR CALLS: Corded mono RJ9 landline phone headset with Noise-canceling microphone filters out background noise, offering the excellent sound quality. Wideband audio delivers clearer conversations, while Acoustic Shock Protection protects our hearing. RJ9 PHONE HEADSET: ONLY WORKS for Some Specific Phone Models from Yealink T19P T20P T21P T22P T26P T28P T41P T23G T32G T38G T40G T42S T46S T48S Avaya 1608 1616 9608G 9611G 9641G J139 J169 Grandstream GXP 1400 1405 1610 1615 1620 1630 2000 2120 2124 2135 Panasonic KXT-2260 2310 2315 2365 2368 7220 Cisco Snom Zultys AltiGen and etc. Not for Cell Phones and Computers.