1,with CE,ROHS,ISO etc 2,professional amplifier,with USB,TF,MPS input 3,several colors to selection:pink,black, ... resistance Tone clear Applicable area of 400 square meters This Portable Voice Amplifier gives you the freedom to move around your stage ... use, can make MP3 player With USB,SD/MMC MP3 input With echo function Audio Amplifier Technology:Audio amplifiers feed electric power ...