Xtenzi Pioneer Car DVD Nvigtion Bluetooth Microphone Mic Assembly CPM1084 CPM1083 Adopting electret condenser cartridge with high sensitivity , low impedance , anti noise and ant jamming capability , with fast and accurate data transmission, which could guarantee the voice clearly and stably under kinds driving occasions, it's highly improved the speech quality of hand free car kit communication system. Adopting humanity design with U shape fixing clip , is more easy to install and reliable. Standard Operation Voltage: 4.5V Operation Voltage: 1.0V-10V.DC Wire Length: 4 M