Perfect device for 2 people communicating when driving motorcycle.Features:Freely talking with high quality voice.Adjustable microphone， so easy to control.2 volume controller for both earphones.Enjoy stereo audio from portable sets(CD， MP3， MP4，two way radio，cellphone etc).Mini appearance for convenient operation.Made of durable material， long time use.Lower power consumption.Specifications:Color: BlackPower source: UM-4(size AAA) * 2 piecesRated output: 150mWFrequency response: 50 to 20，000Hz +/-3dBOutput circuit: 32Ω， 150mW， 84dB±3dBHost dimension: 63 * 56 * 25mmOperating temperature: -20 to +50 degreePackage Size: 30 * 20 * 3cm / 11.8 * 7.9 * 1.2inPackage Weight: 144g / 5.1ozPackage List:1 * Intercom Host2 * Earphone with Mic1 * Audio Cable1 * English User Manual