Wide Compatibility: Wired phone headset with RJ9 jack is compatible with mainstream IP phones, such as AVAYA 1408 9508 Aastra 6753i AudioCodes 450HD Polycom 550 670 Altigen Fanvil X3 X5 Nortel Atcom Gigaset etc. PLEASE CHECK THE COMPATIBILITY LIST BEFORE BUY THE HEADSET TO AVOID THE COMPATIBILITY ISSUES. Designed for Call Centers: With professional office phone headset, you can deal with 8 hours' calls easily even in busy call centers. Headsets free your hands from cradling the handset with shoulder and neck. This monaural headset can be worn on eighter ear. High Strength: MKJ call center headset is made of quality PU materials, plastic parts and Kevlar-reinforced cord to ensure high strength and the lasting performance in busy environments, such as contact center, telemarketing offices, home-based phone jobs. Integrated instructure makes this desk phone headset more durable. All-day Comfort: MKJ wired headphones with mic gives you all the features you need in the offices, not only the crystal clear sound, but also the wearing comfort. Lightweight design, luxurious headpad, soft ear cushion, adjustable headband enable you have a great wearing experience, 330°rotatable microphone arm and 180°rotatable headband allow you to find a perfect fit. Excellent Sound: This corded phone headset with microphone is designed for users to handle the heavy calls. With this RJ9 telephone headset, you are able to get other tasks during the phone calls. Featuring with an ultra noise canceling microphone and wideband audio technology, this landline phone headset deliver crystal clear sound and you can hear clearly from your callers.