... card,USB Portable SD/TF/USB/MMC Cards MP3 Player/Speaker HOT1)ROHS,CE,FCC 2)With USB ... parameters:1. Application: notebook computers, mobile phones, MP3, MP4, DVD, CD, U plate and the audio equipment outside put.2 ... . Frequency range: 50 Hz ac-20 KHz6. The built-in battery: 2000 ma7. Speaker specification: 2 inches * 28 ... magnetic, 4 ohmTweeters: 2.75 inches in diameter (70 mm), the magnetic, four ohms