iRV68 car stereo is featured independent Zone 3 control and supports Bluetooth/HDMI in&out with ARC/AM/FM/CD/DVD/MP3/MP4/Clock, providing digital 5.1 Surround Sound-optical SPDIF Audio Input. This RV stereo has digital amplifier for audio output, no heat low temperture in your mounting cabinet. USB is used to play music, video and photo file, also used to charge Android phones. This car audio receiver has a built in clock that can display the time in any mode.