Wireless FM transmission lets you enjoy your favorite MP3 music in your car or your boat the most convenient wayInsert into your car or boat's 12V cigarette lighter socketBuild in FM Stereo Transmitter Module to broadcast the MP3 music to radio channelsAdjustable frequency. Choose the least interfered frequency between 87.7 and 88.9 MHz for your car radioUSB Host Control Interface to read most kinds of USB Flash DrivesU.S. FCC certified. FCCID:RWH-MP308-00DC-12V operating with car cigar lighter power outletSupports most brands of USB 1.1 and 2.0 flash drives (pen drives) Supports most brands of MP3 Player、CD、MD、DVD PlayerDecoder supports MP3 music filesOutput: 5V,300MAOperating temperature: -30℃~+80℃Storage temperature: -40℃~+85℃Dimension: 90x38x22mm ( L x W x H ) Weight: 45g Transmission range: 3 metersLED indicates light: Power on/System on-LED onFrequency channel setting by SW: FM channel preset(87.7,87.9,88.1,88.3,88.5,88.7,88.9MHZ)