... technology,research,design,manufacturing,production,marketing,and after-sale service to execute the principle"Customer first ,quality best and credit ... . Ideal for gifts and promotional items4. Portable and easy to operate5. Built-in li-on battery or external battery box ... .5mm dudio cable7. Built-in digital amplifier, saving energy8. Adapt to computer, laptop, DVD, VCD, CD, MP3, TV, mobile phone and ...