This product is FM/MP3 Transmitter. It transmits output signals of various equipments (e.g. portable CD, DVCD, MD, MP3) with frequency modulation, then these signals are received and played by automobile audio equipment. You can enjoy high-quality music conveniently and economically. Technical Parameters Valid Range: 30m Operating Current: 40?0mA Operating Voltage:12V,24V Emission Power: 10mW Channel Isolation: ≧75db Output Frequency: 88.1/88.3/88.5/88.7HZ/88.9/ 106.7/107.1/107.3/107.5/107.9MHZ (Detailed information can be found on the trademark label on the product body) Measurement: 39.5?4?9.5cm Cross Weight: 4kg QTY: 50pcs/case Product Overview FM-01 is a single-frequency FM transmitter. It transmits output signals of various equipments (e.g. portable CD, DVD, MD, MP3, language repeater, voice pen palm and PDAs) with frequency modulation, then these signals are received and played by automobile audio equipment. You can enjoy high-quality audio conveniently and economically. Adopted 3D sound decoding technology, it can reproduce high-quality audio signals from MP3, MD, CD and TV HI-FI equipments. It also introduced Phase Lock Loop (PLL) technology, and ensured the stability of FM signal emission, without any excessive frequency shift.