... 86db,compatibility 4.design for teacher comfort headphone with microphoneFunction:1.Multichannel :It has more than ... a different receiver.1.MIC:headphone, collar or clip,ear-hanging MIC.2.Small size,lightweight, ... 3.Digit designed,instead of any other MIC.4.LED display charging status,balanced ... All-digital transmission, strong anti signal interference, with CD-quality sound.3) Professional ID code ...