What is FM transmitter? The FM transmitter is a device that can convert audio contents from any audio source such as MP3, cellphone, computer etc. to signals that out in FM band, the signals can be picked up by any radio receivers that uses the same frequency. How does FM transmitter work? First connect the audio source to FM transmitter, the audio signals will be converted to FM signals and broadcast out through the antenna via tuned frequency, people at the other end use a radio receiver to hear the audio by tuning to the same frequency. Features: Fast storage button, with five dedicated storage button, can quickly store the commonly used frequency. Support USB sound card input, to avoid the traditional audio transmission,external electrical interference to achieve original sound quality transmission. Powerful microphone function, built-in condenser microphone, support external condenser microphone, with professional KTV microphone reverb, delay effect, and has a good anti-whistle effect. Stable RF power,to solve the transmission power with the battery voltage drop significantly decline in the phenomenon of transmission power is always the same,so as to ensure the stability of the coverage. Specification: Transmitter frequency: 76MHz-108MHz Working hours 6-8 hours Charge Power Supply:5V/1000mA Battery Capacity:3.7V/2000mA Working current:T600M<300mA Frequency Stability:±10PPM Frequency Step:100KHz MP3 decording format :FLAC,WAV,PCM,WMA,MP3 Audio distortion:0.1% Frequency Response:30Hz-15000Hz Signal to noise ratio:?70dB Net weight:2.68oz Package content: 1 x FM transmitter 1 x Antenna 1 x USB charging cable 1 x Lapel Clip-on Microphone 1 x lanyard 1 x Car charger 1 x English manual