Directly talk via bluetooth,working as interphone,More than 100 or 500m Intercom. Real twoway wireless communication between three riders by Bluetooth system Receive and reject phone call,call out and hang up.Auto answer phone call. Stereo music/audio function(transmits from A2DP enabled phone/MP3/GPS) Could be connected with GPS. Up to 7 hours talking time Freely switch between Phone call,Bluetooth Intercom,Music. DSP Noisy supression technology and Mic echo cancellation to ensure high quality sound even in high speed. Up to 120 Km working speed. Water-resistance,all weather-Perfectly Work! Universal audio input for audio devices, such as MP3, MP4 to enjoy wire stereo listening Advanced A2DP & EDR bluetooth profile. Maximum talking range 100 or 500 meters between two riders, real two-way wireless communication between three riders by bluetooth system. FM radio frequency function covers 76~108MHz.