Technical Pro HW4000U Digital Hybrid Amplifier/Preamp/ Tuner with USB/SD Card Inputs and Dual Wireless Microphones 4000 watts peak power Dual VHF high band wireless microphones included Inputs: RCA (2CH, 5.1CH) USB Flash Drive & SD Card Outputs: Banana binding post (4 speakers), RCA (record line, preamp, 2 mono to subwoofer) USB & SD Card maximum size: 8GB Plays .mp3 files Bass, treble and balance controls Dual 1/4'' mic inputs with volume, echo, bass and treble controls Separate gain control