For sale, we have a rare Allison Acoustics "The Electronic Subwoofer Audio Bandpass Filter and EQ" The unit comes from a collector who had a number of Allison speakers that we acquired. The unit looks to be all original on the inside. It has been tested and it is in working order. Prior to testing, we cleaned the switches and then treated with Deoxit D5. All RCA connections were cleaned and polished. There are several scuffs and scratches on the unit, but it presents itself very well.