The Terratrip Professional Intercom Amplifier is designed to give the best communication between a driver and co-driver. The amplifier has a noise reduction system that eliminates the background noise such as the engine, preventing excessive sound levels in the headsets. Powered by the vehicles 12v power supply so there is no need to keep changing internal batteries. The Professional Amplifier has separate volume controls for the driver and co-driver.It has a two way radio interface connection and an output socket for Mp3 recorder or video camera, plus an audio input for music or other audio devicesAutomatic volume control to prevent excessive background noise volume in the head setsNoise limiter to reduce loud noises for a brief period, so if your navigator shouts you wont be deafened.The Terratrip Professional intercom amplifier is no longer available with built in Bluetooth connectivity but if connection to a mobile phone is required this can be done by purchasing an adaptor lead (T