RioRandRR-HY-502 USB SD MP3 FM Digital Display Player Boat Car Motorcycl Amplifier 20W+20W DC12V Blue Powered by RioRand Advanced Technology Can play U disk SD/MMC card for music and FM stereo radio, support MP3 music format. Pre-professional level input operational amplifier IC for circuit design, sound, transparent, bright; Filtering and anti-large-capacity power circuit DSP sound field pattern of the four Two main channel output