1,with CE,ROHS,ISO etc 2,professional amplifier,with USB,TF,MPS input 3,several colors to selection:pink,black ... 95x80x35 mmColor: pink ,red,black,white Features:The Rechargeable Voice Amplifier adopts ABS engineering plastic, impact resistance Tone clear Applicable area ... certain unavoidable amount of distortion as the amplifier adds more power to the audio signal, tube amplifiers tend to distort in a ...