... , cell phones, PSP, etc, supports USB, SD card, MP3/WMA files, with built-in FM radio (option). • Support: USB, SD card, mp3, WMA files ... audio line• Power supply: USB, li-ion battery• Output power: the RMS 3W x 2• Frequency: 100HZ - 18KHZ• Speaker: Φ45mm x 2 ... /4Ω• S/N Ratio: ≥75db• Material: ABS• FM (Optional)