OvisLink noise cancelling headset OVHS084-MTL is a dual ear call center headset compatible with Mitel phones. It is a call center headset with noise cancelling microphone. This headset model is compatible with all Mitel phones which have RJ9 headset jack. It comes with a RJ9 Quick Disconnect cord that connects the headset directly to Mitel Business phone's headset jack. No amplifier, no adapter is needed. Headset volume, mute function can be controlled by the pressing buttons on the phone's keypad. To activate or deactivate the headset connected with the phone, simply press the headset button on the telephone keypad. This OvisLink Call Center headset model services user with solid, crystal clear voice quality. This is a corded call center headset with Over-the-Head design. With the flexible, microphone boom. The headset features with Acoustic Shock Protection (when the electric overcharge signal of 6v or above comes to the receiver, it will be cut off automatically), Noise Cancellation microphone, lightweight, leatherette ear cushion, flexible microphone boom, adjustable headband and Tangle-Free coiled Quick Disconnect cord. This OvisLink Call Center Headset is designed for call center agents to wear all-days and feel comfort. Phone models Compatible: Mitel MiVoice phone models: 4422, 4425, 5312, 5320, 5320e, 5324, 5330e, 5360, 5540, 6390, 6392, 8528, 8568 AASTRA phone models: i220, 4222, 4223, 4224, 4225, 480e, 480i, 6710a, 6725i, 6730a, 6735i, 6737i, 6739i, 6753i, 6755i, 6757i, 7147a, 7187a, 9112i, 9133i, 9143i, 9480iIf you prefer headset with two earpieces on both ears, please choose the headset model OVHS072-MTL, ASIN # B00K1R5QCY. Many phone models need to setup headset mode on the phone in order to use a headset. Check headset manufacture OvisLink website to get detail instruction.