Four-Channel Professional Microphone Input Device with Built-in Acoustical Echo Cancelation. The EasyUSB PRO MIC I/O is designed to integrate any professional microphone with Vaddio’s™ EasyUSB audio solutions. The PRO MIC I/O incorporates Vaddio’s unique SmartMIC technology into the mixer, providing distributed multi-channel acoustical echo cancelation and automatic microphone mixing. Additional DSP/Digital Signal Processing technologies include noise reduction, microphone gating, equalization, filtering and AGC for automatically calibrating to the live requirements of the room. The PRO MIC I/O comes equipped with four independent echo cancelation microphone inputs and one discreet output for interfacing to the Vaddio EasyUSB Mixer/Amp. The system can be expanded to support eight microphones by adding an additional PRO MIC I/O. This Package Includes: – EasyUSB PRO MIC I/O Interface – Quick-Start Guide – 1 qty 4-position phoenix-style connector – 4 qty rubber feet for the bottom of EasyUSB MicPOD I/O unit if not rack-mounted