The Plantronics vista m22 is an amplifier that allows you to improve the call quality of any Plantronics h-series headset. With the ability to make adjustments and ultimately eliminate background noise/distortion, the vista m22 will prove to be a valuable accessory. The vista m22 is the perfect solution if your phone doesn’t have a headset port. The m22 plugs into your phone’s handset port, while your handset and headset plug into the m22, essentially adding a headset port to your phone. This Plantronics m22 is powered via two aa batteries or external power supply which are sold separately.