1,KTV Sound effects 2,Echo and reverberation 3,Switch track 4,Recharge function 5,Easy Combination Specification:Product Size: ... :15mW Material:ABS Frequency Response: 30HZ-20KHZRechargable Li-Battery:400mAH ,3.7V sound amplifying range:+1dB--+25dBSound pressure:≥130dB(at 1kHz ... audio cable,support MP3,PC,ipod, CD etc., sound source.3, More portable,smarter, more ecnomic,more practical.4.support echo ...