Purpose: karaoke, dancing,old people doing morning exercises,entertainment,outdoor guitar playing,teaching and lecture,broadcast,ect;Features: built-in rechargeable battery, support SD/USB/MP3, wired headset,audio input;Power supply: 12 v and 24 v - 110 - v - 220 - v;Power: 120 w;Speaker: 4 inches*1;impedance:4 Ω;Sensitivity: 90 db;Frequency response range: 60 hz - 20 KHZ;Size: 310 * 100 * 200 (mm);Accessories: wired headsets, remote control, the power cord.