Real time all analogue phase sweep between zero and one hundred and eighty degrees... and everything in-between. Allows mics to be placed where they sound best individually, compromising mic placement due to phase problems is not necessary when using the ibp. +4dB XLR balanced input and outputs. Internal super quality active transformer isolated line level direct box. Re-amp capability for bringing +4dB line level signal to guitar level. Buffered instrument level output for driving long guitar cable. Allows splitting between two instrument amps with transformer isolation and phase sweep. Rack mountable 4 IBPs fit in a1U 19" standard rack space. Extremely high quality construction. Made in the U.S.A.