7 Mic & 2 Aux Inputs. Built-in MP3 player with remote control for USB, SDMMC card reader. Preamplifier and Line Output for connecting to a Booster Amplifier. Line Input for connecting the output from any external mixer or another amplifier. Resettable circuit breaker for protection against overload and short circuit. Instant transfer to DC power (Car Battery) if AC power fails. Box SpeakerDriver Unit selector switch. Bass boost defeated at Driver Unit position for safer operation of driver units.