The USA-740 offers the same classic look that Custom Autosound has always been known for with today's latest features. Now, with built-in Bluetooth (microphone included), answer calls and get Bluetooth streaming music from your Bluetooth capable phone or Bluetooth compatible device. A solid 300-watt peak power should be all the juice you need, yet the USA-740 has Hi 4volt, 4channel RCA Pre-outs and a Subwoofer RCA pre-out for additional amplifiers. The USB input allows you to plug in a USB flash drive (thumb drive) for playback of MP3/WMA/FLAC/WAV song files. A front mini jack auxiliary audio input and a rear RCA auxiliary audio input provide versatility for options like satellite radio, I-pod or any portable player you wish to use.