... .USB,SD card reader 4.OEM service 5.Magnetically shielded 2.1 HOME THEATER SYSTEMFrequency response: 40Hz-150Hz, 150Hz-20KHzOutput Power: 30W+10Wx2 Speaker ... : Volume, bass, treble knobs on sideUsage: Home Theatre,Stage,Portable Audio Player,USB, SD, PC, laptop, DVD, VCD, CD with music back ...